St. Augustine’s Confessions is one of the most important works in the history of literature and Christian thought. Written around 397, when Augustine was the Christian bishop of Hippo (in modern-day Algeria), the Confessions were designed both to spiritually educate those who already shared Augustine’s faith, and to convert those who did not. Augustine did this through the original maneuver of writing what is now recognized as being the first Western autobiography – letting readers share in his own experiences of youth, sin, and eventual conversion.

The Confessions are a perfect example of using reasoning to subtly bring readers around to a particular point of view – with Augustine inviting them to accompany him on his own spiritual journey towards God so they could make their own conversion. Carefully structured, the Confessions run from describing the first 43 years of Augustine’s life in North Africa and Italy, to discussing the nature of memory, before moving on to analyzing the Bible itself. In order, the sections form a carefully structured argument, moving from the personal to the philosophical to the contemplative. In the hundreds of years since they were first published, they have persuaded hundreds of thousands of readers to recognize towards the same God that Augustine himself worshipped.

John Locke's 1689 Two Treatises of Government is a key text in the history of political theory - one whose influence remains marked on modern politics, the American Constitution and beyond. Two Treatises is more than a seminal work on the nature and legitimacy of government. It is also a masterclass in two key critical thinking skills: evaluation and reasoning. Evaluation is all about judging and assessing arguments - asking how relevant, adequate and convincing they are. And, at its heart, the first of Locke's two treatises is pure evaluation: a long and incisive dissection of a treatise on the arguments in Sir Robert Filmer's Patriarcha. Filmer's book had defended the doctrine that kings were absolute rulers whose legitimacy came directly from God (the so-called "divine right of kings"), basing his arguments on Biblical explanations and evidence. Locke carefully rebutted Filmer's arguments, on their own terms, by reference to both the Bible and to recorded history. Finding Filmer's evidence either to be insufficient or unacceptable, Locke concluded that his argument for patriarchy was weak to the point of invalidity. In the second of Locke's treatises, the author goes on to construct his own argument concerning the sources of legitimate power, and the nature of that power. Carefully building his own argument from a logical consideration of man in "the state of nature", Locke creates a convincing argument that civilised society should be based on natural human rights and the social contract.

Few works can claim to form the foundation stones of one entire academic discipline, let alone two, but Thucydides's celebrated History of the Peloponnesian War is not only one of the first great works of history, but also the departure point from which the modern discipline of international relations has been built. This is the case largely because the author is a master of analysis; setting out with the aim of giving a clear, well-reasoned account of one of the seminal events of the age - a war that resulted in the collapse of Athenian power and the rise of Sparta - Thucydides took care to build a single, beautifully-structured argument that was faithful to chronology and took remarkably few liberties with the source materials. He avoided the sort of assumptions that make earlier works frustrating for modern scholars, for example seeking reasons for outcomes that were rooted in human actions and agency, not in the will of the gods. And he was careful to explain where he had obtained much of his information. As a work of structure - and as a work of reasoning - The History of the Peloponnesian War continues to inspire, be read and be taught more than 2,000 years after it was written.

W.E.B Du Bois' The Souls of Black Folk is a seminal work in the field of sociology, a classic of American literature - and a solid example of carefully-structured reasoning. One of the most important texts ever written on racism and black identity in America, the work contains powerful arguments that illustrate the problem of the position of black people in the US at the turn of the 20th-century. Du Bois identified three significant issues ('the color line'; 'double consciousness'; and 'the veil') that acted as roadblocks to true black emancipation, and showed how each of these in turn contributed to the problem of inequality. Du Bois carefully investigates all three problems, constructing clear explanations of their significance in shaping the consciousness of a community that has been systematically discriminated against, and dealing brilliantly with counter-arguments throughout. The Souls of Black Folk went on to profoundly influence the civil rights movement in the US, inspiring post-colonial thinking worldwide.

Emile Durkheim's 1897 On Suicide is widely recognized as one of the foundational classic texts of sociology. It is also one that shows the degree to which strong interpretative skills can often provide the bedrock for high-level analysis. Durkheim's aim was to analyse the nature of suicide in the context of society itself - examining it not just as an individual decision, but one in which different social factors played important roles. In order to do this, it was vital that he both define and classify suicide into subtypes - kinds of suicide with different causal factors at play. From his research, Durkheim identifed four broad types of suicide: egoistic (from a sense of not-belonging), altruistic (from a sense that group goals far outweigh individual well-being), anomic (from lack of moral or social direction), and fatalistic (in response to excessive discipline or oppression). These definitions opened the way for Durkheim to pursue a close social analysis examining how each type related to different social contexts. While his study is in certain ways dated, it remains classic precisely because it helped define the methodology of sociology itself - in which interpretative skills remain central.

Frantz Fanon's explosive Black Skin, White Masks is a merciless expose of the psychological damage done by colonial rule across the world. Using Fanon's incisive analytical abilities to expose the consequences of colonialism on the psyches of colonized peoples, it is both a crucial text in post-colonial theory, and a lesson in the power of analytical skills to reveal the realities that hide beneath the surface of things. Fanon was himself part of a colonized nation - Martinique - and grew up with the values and beliefs of French culture imposed upon him, while remaining relegated to an inferior status in society. Qualifying as a psychiatrist in France before working in Algeria (a French colony subject to brutal repression), his own experiences granted him a sharp insight into the psychological problems associated with colonial rule. Like any good analytical thinker, Fanon's particular skill was in breaking things down and joining dots. His analysis of colonial rule exposed its implicit assumptions - and how they were replicated in colonised populations - allowing Fanon to unpick the hidden reasons behind his own conflicted psychological make up, and those of his patients. Unflinchingly clear-sighted in doing so, Black Skin White Masks remains a shocking read today.

Understanding why revolutions take place when they do, and as they do, is important in itself. Understanding how they are rooted in the societies they upend - and the ways in which those societies share crucial similarities - is arguably even more so. The enduring influence of Jack Goldstone's Revolution and Rebellion lies as much in the challenge that it issues to the long-dominant model of 'western exceptionalism' (the idea that it was early modern Europe's distinctive history that launched it on the path to world domination) as it does in the book's persuasive account of revolutions rooted in a four stage process that advances from fiscal crisis, through inter-elite conflict and mass-mobilization potential, to the breakdown and re-making of culture and ideology. It can be argued that this unexpected outcome - one that the author himself did not anticipate - is the product of an acute problem-solving ability, one that made Goldstone particularly receptive to alternative possibilities. His insistence that early modern and modern European and Asian peoples have vastly more in common than was generally recognised, and followed a similar path of advanced organic development that left Qing China as vulnerable to revolution as the France of the Ancien Regime, has not only become a central contention of early 21st century sociology; it has also underpinned the creation of multiple theoretical models that have nothing to do with revolution. None of this would have been possible had not Goldstone challenged himself by asking questions that other scholars had supposed had mundane answers.

C. Wright Mills's 1959 book The Sociological Imagination is widely regarded as one of the most influential works of post-war sociology. At its heart, the work is a closely reasoned argument about the nature and aims of sociology, one that sets out a manifesto and roadmap for the field. Its wide acceptance and popular reception is a clear demonstration of the rhetorical power of Wright's strong reasoning skills. In critical thinking, reasoning involves the creation of an argument that is strong, balanced, and, of course, persuasive. In Mills's case, this core argument makes a case for what he terms the "sociological imagination", a particular quality of mind capable of analyzing how individual lives fit into, and interact with, social structures. Only by adopting such an approach, Mills argues, can sociologists see the private troubles of individuals as the social issues they really are. Allied to this central argument are supporting arguments for the need for sociology to maintain its independence from corporations and governments, and for social scientists to steer away from 'high theory' and focus on the real difficulties of everyday life. Carefully organized, watertight and persuasive, The Sociological Imagination exemplifies reasoned argument at its best.

Emile Durkheim’s 1897 On Suicide is widely recognized as one of the foundational classic texts of sociology. It is also one that shows the degree to which strong interpretative skills can often provide the bedrock for high-level analysis.

Durkheim's aim was to analyse the nature of suicide in the context of society itself – examining it not just as an individual decision, but one in which different social factors played important roles. In order to do this, it was vital that he both define and classify suicide into subtypes – kinds of suicide with different causal factors at play. From his research, Durkheim identifed four broad types of suicide: egoistic (from a sense of not-belonging), altruistic (from a sense that group goals far outweigh individual well-being), anomic (from lack of moral or social direction), and fatalistic (in response to excessive discipline or oppression). These definitions opened the way for Durkheim to pursue a close social analysis examining how each type related to different social contexts.

While his study is in certain ways dated, it remains classic precisely because it helped define the methodology of sociology itself – in which interpretative skills remain central.

Charles Darwin called on a broad and unusually powerful combination of critical thinking skills to create his wide-ranging explanation for biological change, On the Origin of Species.

It’s one of those rare books that takes a huge problem – the enormous diversity of different species – and seeks to use a vast range of evidence to solve it. But it was perhaps Darwin’s towering creative prowess that made the most telling contribution to this masterpiece, for it was this that enabled him to make the necessary fresh connections between so much disparate evidence from such a diversity of fields.

All of Darwin’s critical thinking skills were required, however, in the course of the decades of work that went into this volume. Taken as a whole, Darwin’s solution to the problem that he set himself is carefully researched, considers multiple explanations, and justifies its conclusions with well-organised reasoning. At the time of the publication, in 1859, there were various explanations for the changes that Darwin – and others – observed; what separated Darwin from so many of his contemporaries is that he deployed critical thinking to arrive at a significantly new way of fitting explanation to evidence; one that remains elegant, complete and predictive to this day.

There is arguably no more famous book about the arts of interpretation and analysis than Sigmund Freud’s 1899 Interpretation of Dreams. Though the original edition of just 600 copies took eight years to sell out, it eventually became a classic text that helped cement Freud’s reputation as one of the most significant intellectual figures of the 19th and 20th centuries. In critical thinking, just as in Freud’s psychoanalytical theories, interpretation is all about understanding the meaning of evidence, and tracing the significance of things. Analysis can then be brought in to tease out the implicit reasons and assumptions that lie underneath the interpreted evidence.

Interpretation of Dreams is a masterclass in building telling analyses from ingenious interpretation of evidence. Freud worked from the assumption that all dreams were significant attempts by the unconscious to resolve conflicts. As a result, he argued, they contain in altered and disguised forms clues to our deepest unconscious urges and desires. Each must be taken on its own terms to tease out what they really mean. Though Freud’s theories have often been criticized, he remains the undisputed master of interpretation – with his critics suggesting that he was, if anything, too ingenious for his own good.

No philosopher could be a better example of creative thinking in action than Friedrich Nietzsche: a German iconoclast who systematically attacked the traditionally accepted views of academic philosophers, seeking to tear down their rickety platform and replace it with a platform of his own. Creative thinkers are people who redefine issues and topics in novel ways to create novel connections, explanations and hypotheses – people, in short, who can turn a topic on its head and present it in an entirely new light. Nietzsche called them “free spirits” – those unwilling to accept the dogmas of the past, wanting instead to think clearly for themselves.

In Beyond Good and Evil, Nietzsche focuses his attention on nothing less than the underlying basis of our moral assumptions, unleashing a powerful, polemical critique of the moral dogmas of the past and his own time. His book, which remains one of the most influential works of moral philosophy ever written, is not just an example of creative thinking at work, it is also a passionate argument for its importance. As Nietzsche wrote, “Morality in Europe … is the morality of herd animals.” But if one is ready to think differently and stand out from the herd, “other (and especially higher) moralities are … possible.”

In his 1997 work Guns, Germs and Steel, Jared Diamond marshals evidence from five continents and across 13,000 years of human history in an attempt to answer the question of why that history unfolded so differently in various parts of the globe. His results offer new explanations for why the unequal divisions of power and wealth so familiar to us today came into existence - and have persisted. Balancing materials drawn from a vast range of sources, addressing core problems that have fascinated historians, anthropologists, biologists and geographers alike - and blending his analysis to create a compelling narrative that became an international best-seller and reached a broad general market - required a mastery of the critical thinking skill of reasoning that few other scholars can rival. Diamond's reasoning skills allow him to persuade his readers of the value of his interdisciplinary approach and produce well-structured arguments that keep them turning pages even as he refocuses his analysis from one disparate example to another. Diamond adds to that a spectacular ability to grasp the meaning of the available evidence produced by scholars in those widely different disciplines - making Guns, Germs and Steel equally valuable as an exercise in high-level interpretation.

The history of anthropology is, to a large extent, the history of differing modes of interpretation. As anthropologists have long known, examining, analyzing and recording cultures in the quest to understand humankind as a whole is a vastly complex task, in which nothing can be achieved without careful and incisive interpretative work. Edward Evans-Pritchard's seminal 1937 Witchcraft, Oracles, and Magic Among the Azande is a model contribution to anthropology's grand interpretative project, and one whose success is based largely on its author's thinking skills. A major issue in anthropology at the time was the common assumption that the faiths and customs of other cultures appeared irrational or illogical when compared to the "civilized" and scientific beliefs of the western world. Evans-Pritchard sought to challenge such definitions by embedding himself within a tribal culture in Africa - that of the Azande - and attempting to understand their beliefs in their proper contexts. By doing so, Evans-Pritchard proved just how vital context is to interpretation. Seen within their context, he was able to show, the beliefs of the Azande were far from irrational - and magic actually formed a coherent system that helped mould a functional community and society for the tribe. Evans-Pritchard's efforts to clarify meaning in this way have proved hugely influential, and have played a major part in guiding later generations of anthropologists from his day to ours.

The Anti-Politics Machine (1990) examines how international development projects are conceived, researched, and put into practice. It also looks at what these projects actually achieve. Ferguson criticizes the idea of externally-directed 'development' and argues that the process doesn't take proper account of the daily realities of the communities it is intended to benefit. Instead, they often prioritize technical solutions for addressing poverty and ignoring its social and political dimensions, so the structures that these projects put in place often have unintended consequences. Ferguson suggests that until the process becomes more reflective, development projects will continue to fail.

Claude Levi-Strauss is probably the most complex anthropological theorist of all time. His work continues to influence present-day thinkers in his field, but he is perhaps even more influential beyond it. As one of the key figures in the development of what is known today as 'French theory,' Levi-Strauss was one of the most important thinkers of the 20th-century. His theories of interpretation, meaning and culture have helped shape the ideas and methodologies of a range of disciplines, above all literature and philosophy. At the heart of Levi-Strauss's work are the questions of meaning and where meaning comes from. As an anthropologist, he was primarily interested in what completely different and separate cultures might have in common. Crucially, he saw how common ground resides not on the surface of cultures (i.e., in similar customs), but deep inside invisible background structures of thought. His quest was to peel away the surface of different cultures through careful interpretation, advancing from one layer to another until he discovered the structures that lay behind all of the exterior practices and meanings. Infamously challenging, his work shows interpretative skills working at the highest, most abstract level possible.

Robert Lucas is known among economists as one of the most influential macroeconomists of recent times - a reputation founded in no small part on the critical thinking skills displayed in his seminal 1990 paper 'Why Doesn't Capital Flow from Rich to Poor Countries?' Lucas's paper tackles a puzzle in economic theory that has since come to be known as the 'Lucas paradox,' and it deploys the author's brilliant problem solving skills to explain why such an apparent paradox in fact makes sense. Classical economic theory makes a simple prediction of how capital flows between countries: it should, it states, flow from rich to poor countries, because of the law of diminishing returns on capital. Since poor countries have so little capital invested in them, the returns on new investment should be proportionally far better than investment in rich countries. This should mean that investors seeking new opportunities will invest in poorer countries, making capital consistently flow from rich nations to poorer ones. But, problematically, this is not in fact the case. Having defined the problem, Lucas did what any good problem solver would: he looked critically at the criteria involved, and offered a series of possible solutions. Indeed, in just six pages, he puts forward four hypotheses to explain the paradox's existence. The popularity of his paper, and the influence it has had, are also greatly magnified by careful reasoning embodied in Lucas's marshalling of evidence and his explanations of the judgements he has made.

What is the ultimate goal of any human society? There have been many answers to this question. But by producing a series of notably well-structured arguments, economist Mahbub ul Haq's Reflections on Human Development persuaded readers that the goal should be defined quite simply as the requirement that each society improve the lives of its citizens. If this is the agreed aim, Haq continues, then economic development should be designed to support human development. His well-structured reasoning helped development economists recalibrate much of what had previously been regarded as self-evident; that economic productivity was the main barometer of social well being. The work had a profound effect, and Haq's thinking helped produce a new understanding of what 'development' actually meant. Haq conscientiously mapped out arguments and counter-arguments to persuade readers that development did not simply mean an increase in productivity, but rather an increase in human development - the capability of people to live the lives they want to. By bringing the abstract back to the concrete, Haq reevaluated the neoliberal reasoning that suggested economic development necessarily benefitted everybody. And, by virtue of his strong command of reasoning, Haq showed how economic development provided no guarantees that rich people would spend money on improving health, education or other human development outcomes for the poor.

Our Common Future is a joint work produced in 1987 by a United Nations commission headed by former Norwegian Prime Minister, Gro Brundtland. Also known as The Brundtland Report, it offers a classic approach to problem solving by first asking a productive question. How do we protect the world we live in for future generations, while at the same time stimulating economic and social development right now? The solution the work proposes is "sustainable development", defined in the report as humanity's ability "to ensure that it meets the needs of the present without compromising the ability of future generations to meet their own needs." The key conclusion the report came to - that we need long-term strategies to manage the earth's natural resources - proved to be so universally welcomed it introduced the term "sustainability" into the everyday language of international politics. Solving the problem of workable sustainable development became a hot topic, leading to the birth of a new academic discipline, environmental economics. The book offered a solution to the problem of ensuring sustainable development by highlighting the critical importance of international cooperation.

Amartya Sen uses his 1999 work Development as Freedom to evaluate the processes and outcomes of economic development. Having come to the conclusion that development is best summed up as the expansion of freedom, Sen examines traditional definitions and understandings of the term. He says people tend to think of freedoms as economic (the freedom to enter into market exchanges) or political (the freedom to vote and be an active citizen), and tries to understand why the definition has been so narrow hitherto. He concludes that an evaluation of true freedom must necessarily include the freedom to access social services such as healthcare, sanitation and nutrition, just as much as it must acknowledge economic and political freedoms. Evaluating the relevance of the current thinking behind development, Sen concludes that the term 'freedom' cannot simply be about income. In many ways, measuring income does not account for various "unfreedoms" (manmade or natural bars to wellbeing) that hinder development. Sen's evaluation is all the more powerful for its clarity: "The freedom-centered perspective has a generic similarity to the common concern with "quality of life."

To the dismay of many commentators - who had hoped the world was evolving into a more tolerant and multicultural community of nations united under the umbrellas of supranational movements like the European Union - the nationalism that was such a potent force in the history of the 20th-century has made a comeback in recent years. Now, more than ever, it seems important to understand what it is, how it works, and why it is so attractive to so many people. A fine place to start any such exploration is with Ernest Gellner's seminal Nations and Nationalism, a ground-breaking study that was the first to flesh out the counter-intuitive - but enormously influential - thesis that modern nationalism has little if anything in common with old-fashioned patriotism or loyalty to one's homeland. Gellner's intensely creative thesis is that the nationalism we know today is actually the product of the 19th-century industrial revolution, which radically reshaped ancient communities, encouraging emigration to cities at the same time as it improved literacy rates and introduced mass education. Gellner connected these three elements in an entirely new way, contrasting developments to the structures of pre-industrial agrarian economies to show why the new nationalism could not have been born in such communities. He was also successful in generating a typology of nationalisms in an attempt to explain why some forms flourished while others fizzled out. His remarkable ability to produce novel explanations for existing evidence marks out Nations and Nationalism as one of the most radical, stimulating - and enduringly influential - works of its day.

Few works of history make as well-structured a case for the importance of studying continuity, rather than change, than Albert Hourani's A History of the Arab Peoples. Hourani's work had three major aims: to refute the idea that Arab society stagnated between 1000 and 1800; to study the period through the lens of diverse Arab, rather than Muslim, history; and to stress intellectual and cultural continuity. All of these intentions were the product of the author's evaluation of a great mass of secondary sources, many of them devoted to arguing for ideas that contradicted his, and it demanded considerable skill to synthesize from them a coherent and well-evidenced counter-argument. Hourani was able to do this largely because his grasp of the relevance and adequacy of his predecessors' arguments was second to none; his achievement lies in his ability to reject the reasoning of other historians while still making good use of their evidence. In this task, he was aided by an interpretative skill almost equal to his powers of evaluation; A History of the Arab Peoples is also a monument to the importance of properly understanding the meaning of available evidence.

Few historians can claim to have undertaken historical analysis on as grand a scale as Geoffrey Parker in his 2013 work Global Crisis: War, Climate Change and Catastrophe in the Seventeenth Century. It is a doorstop of a book that surveys the 'general crisis of the 17th century,' shows that it was experienced practically throughout the world, and was not merely a European phenomenon, and links it to the impact of climate change in the form of the advent of a cold period known as the 'Little Ice Age.' Parker's triumph is made possible by the deployment of formidable critical thinking skills - reasoning, to construct an engaging overall argument from very disparate material, and analysis, to re-examine and understand the plethora of complex secondary sources on which his book is built. In critical thinking, analysis is all about understanding the features and structures of argument: how given reasons lead to conclusions, and what kinds of implicit reasons and assumptions are being used. Historical analysis applies the same skills to the fabric of history, asking how given chains of events occur, how different reasons and factors interact, and so on. Parker, though, takes things further than most in his quest to understand the meaning of a century's-worth of turbulence spread across the whole globe. Beginning by breaking down the evidence for significant climatic cooling in the 17th-century (due to decreased solar activity), he moves on to detailed study of the effects the cooling had on societies and regimes across the world. From this detailed spadework, he constructs a persuasive argument that accounts for the different ways in which the effects of climate change played out across the century - an argument with profound implications for a future likely to see serious climate change of its own.

Frederick Jackson Turner's 1893 essay on the history of the United States remains one of the most famous and influential works in the American canon. That is a testament to Turner's powers of creative synthesis; in a few short pages, he succeeded in redefining the way in which whole generations of Americans understood the manner in which their country was shaped, and their own character moulded, by the frontier experience. It is largely thanks to Turner's influence that the idea of America as the home of a sturdily independent people - one prepared, ultimately, to obtain justice for themselves if they could not find it elsewhere - was born. The impact of these ideas can still be felt today: in many Americans' suspicion of "big government," in their attachment to guns - even in Star Trek's vision of space as "the final frontier." Turner's thesis may now be criticised as limited (in its exclusion of women) and over-stated (in its focus on the western frontier). That it redefined an issue in a highly impactful way - and that it did so exceptionally eloquently - cannot be doubted.

Judith Butler's Gender Trouble is a perfect example of creative thinking. The book redefines feminism's struggle against patriarchy as part of a much broader issue: the damaging effects of all our assumptions about gender and identity. Looking at the factionalism of contemporary (1980s) feminism, Butler saw a movement split by identity politics. Riven by arguments over what it meant to be a women, over sexuality, and over class and race, feminism was falling prey to internal problems of identity, and was failing to move towards broader solidarity with other liberation movements such as LGBT. Butler turned these issues on their head by questioning the basis that supposedly fundamental and fixed identities such as 'masculine/feminine' or 'straight/gay' actually have. Tracing these binary definitions back to the binary nature of human anatomy ('male/female'), she argues that there is no necessary link between our anatomies and our identities. Subjecting a wide range of evidence from philosophy, cultural theory, anthropology, psychology and anthropology to a renewed search for meaning, Butler shows both that sex (biology) and gender (identity) are separate, and that even biological sex is not simplistically either/or male/female. Separating our biology from identity then allows her to argue that, while categories such as 'masculine/feminine/straight/gay' are real, they are not necessary; rather, they are the product of society's assumptions, and the constant reproduction of those assumptions by everyone around us. That opens up some small hope for change: a hope that - 25 years after Gender Trouble's publication - is having a huge impact on societies and politics across the world.