The goal of the Daniel Chalonge School on Astrofundamental Physics is to contribute to a theory of the universe (and particularly of the early universe) up to the marks, and at the scientific height of, the unprecedented accuracy, existent and expected, in the observational data. The impressive development of modern cosmology during the last decades is to a large extent due to its unification with elementary particle physics and quantum field theory. The cross-section between these fields has been increasing setting up Astrofundamental Physics. The early universe is an exceptional (theoretical and experimental) laboratory in this new discipline. This NATO Advanced Study Institute provided an up dated understanding, from a fundamental physics and deep point of view, of the progress and key issues in the early universe and the cosmic microwave background: theory and observations. The genuine interplay with large scale structure formation and dark matter problem were discussed. The central focus was placed on the cosmic microwave background. Emphasis was given to the precise inter-relation between fundamental physics and cosmology in these problems, both at the theoretical and experimental/observational levels, within a deep and well defined programme which provided in addition, a careful interdisciplinarity. Special sessions were devoted to high energy cosmic rays, neutrinos in astrophysics, and high energy astrophysics. Deep understanding, clarification, synthesis, careful interdisciplinarity within a fundamental physics framework, were the main goals of the course.

From the reviews:

"Bulging with concise explanations and 142 clarifying diagrams and photos, the book probably represents some of the best pedagogy in the solar system on these topics. a ] just the right level for most undergraduates. a ] Open-minded scientists looking for an authoritative tour of astrobiology will enjoy the book a ] . The authora (TM)s summary of exoplanet detection techniques is excellent a ] . Jones keeps us interested with simple explanations a ] . His approach is quite an achievement a ] ." (Charley Lineweaver, Physics Today, February, 2005).

"This is a textbook suitable for university use. a ] this is one of the best. a ] includes excellent recent images of Mars, Europa and elsewhere, and is richly illustrated with explanatory diagrams. a ] There is a useful index, a glossary and a list of a ~resourcesa (TM) (websites and books)." (Malcolm Walter, Australian Physics, Vol. 42 (3) July/August 2005)

"What is required for life, and where might it have evolved? a ] These are the questions that are addressed in this wide ranging, well written and thought provoking book. a ] But for anyone wishing to follow a ] Jonesa (TM) book is an excellent start." (Dr. C.M.Linton, Contemporary Physics, Vol. 46 (3), 2005)

"This book centres on the search for life in the Solar System and beyond. It includes an overview of many of the disciplines involved in this field of research, which include astronomy, biology and geology. a ] It was good to see that the astronomy has been kept fairly descriptive and not too mathematical. This keeps the flow of the book. a ] As an overview of the key subjects involved in astrobiology for a university course, I think this book issuccessful." (James Silvester, Astronomy Now, March, 2005)

Although, at present there is no firm evidence for extraterrestrial life, enormous progress has been made in recent years, both in our understanding of life on Earth and of the potential for life existing elsewhere in the universe. Life in the Solar System and Beyond embaces aspects form all the osre related fields (astronomy, planetary science, chemistry, biology, and Physics). This excellent and thought-provoking introduction:

• Addresses the important question of what is life, and discusses the origins and evolution of life on Earth, as well as its probable fate
• Looks at places within our Solar System, beyond Earth, especially where life might exist, such as Mars and Europa
• Includes the very latest data on searches for planets around other stars, the results of these searches, and discusses what conditions might be like
• Speculates on possible life elsewhere in the Universe beyond our Solar system, and assesses our chances of making contact, if there is intelligent life out there
• Includes end of chapter summaries to help the reader grasp the main concepts to carry forward
• Provides a list of resources, including useful websites at the end of the book which will enable the reader to keep up to date in this rapidly moving field

You have just discovered the literary masterpiece that answers your questions about God, life in the inhabited universe, the history and future of this world, and the life of Jesus. The Urantia Book harmonizes history, science, and religion into a philosophy of living that brings new meaning and hope into your life. If you are searching for answers, read The Urantia Book! The world needs new spiritual truth that provides modern men and women with an intellectual pathway into a personal relationship with God. Building on the world's religious heritage, The Urantia Book describes an endless destiny for humankind, teaching that living faith is the key to personal spiritual progress and eternal survival. These teachings provide new truths powerful enough to uplift and advance human thinking and believing for the next 1000 years. A third of The Urantia Book is the inspiring story of Jesus' entire life and a revelation of his original teachings. This panoramic narrative includes his birth, childhood, teenage years, adult travels and adventures, public ministry, crucifixion, and 19 resurrection appearances. This inspiring story recasts Jesus from the leading figure of Christianity into the guide for seekers of all faiths and all walks of life.

"Nothing to sneeze at."–Time

Acclaim for The Secret Life of Dust

"You will never again look disparagingly upon dust. Hannah Holmes has written my favorite kind of book––one that takes a seemingly mundane subject and trumpets its significance in our lives not only on Earth, but in the Heavens."
–– Dr. Neil de Grasse Tyson, Director, Hayden Planetarium and author of One Universe: At Home in the Cosmos

"A fascinating journey into the unseen flecks that underpin our world and those beyond."
–– Peter Tyson, author of The Eighth Continent

"Witty, interesting, and absolutely terrifying."
–– Atlanta Journal-Constitution

"An excellent work. Dust is small, but The Secret Life of Dust is a big, and fun, accomplishment."
–– Austin American-Statesman

"Few browsers will put science writer Hannah Holmes’ latest volume down without adding it to their to-be-read list."
–– Dallas Morning News

"Worth the price on its dust jacket. Holmes’ book belongs on your shelf, in a dusty nook between the works of Diane Ackerman and John McPhee."
–– Chicago Tribune

"It’s an entertaining little book. . . . After reading The Secret Life of Dust, the fluff in your vacuum cleaner will never look quite the same again."
–– New Scientist

"An unusual perspective on things we don’t notice."
–– The Sunday Times

"Hannah Holmes is a science writer to watch. Who ever thought dust could so shine?"
–– Kirkus Reviews

Cometography is the most complete and comprehensive collection of data on comets available. It comes in four self-contained sequential volumes and this, the first, covers ancient times through to the end of the eighteenth century. Cometography uses the most reliable orbits known to determine all the key parameters of each well observed comet. Cometography also provides nontechnical details to help the reader understand how the comet may have influenced various cultures at the time of its appearance. All the information in Cometography has been sourced directly from the original documents, including European monastic histories, Roman, Greek and Muslim texts, Chinese, Japanese and Korean scripts. In many cases, dates of important historical events can be corrected based on the appearance of a comet and identified using this book. Cometography will be valuable to historians of science as well as providing amateur and professional astronomers with a definitive reference on comets through the ages.

The open cluster NGC 6791 is now considered both the oldest and the most metal-rich known. Its age is 8 -10 Gyrs, twice as old as the canonical solar-metallicity cluster M67 (Garnavich et al. 1994; Demarque, Green, & Guenther 1992; Tripicco et al. 1995). That its metallicity is significantly above solar is suggested from moderate-resolution spectroscopy and from a mismatch of its color-magnitude diagram (CMD) with solar-metallicity isochrones. Tripicco et al. (1995) find [Fe/H] = +0.27 to +0.44. The cluster population is rich. In addition to about a dozen red giants and two dozen red horizontal-branch stars, the cluster has several very hot HB stars (Kaluzny & Udalski 1992). Liebert et al. (1994) have shown that the extremely blue stars are mostly sdB/sdO stars and at least 3 or 4 are likely cluster members, the first ever discovered in an open cluster. These may provide the key to the puzzling upturn in ultraviolet flux below 1500A seen in many high-metallicity systems (Burstein et al. 1988; Ferguson et al. & Liebert 1993).

A fundamental, profound review of the key issues relating to the early universe and the physical processes that occurred in it. The interplay between cosmic microwave background radiation, large scale structure, and the dark matter problem are stressed, with a central focus on the crucial issue of the phase transitions in the early universe and their observable consequences: baryon symmetry, baryogenesis and cosmological fluctuations. There is an interplay between cosmology, statistical physics and particle physics in studying these problems, both at the theoretical and the experimental / observational levels. Special contributions are devoted to primordial and astrophysical black holes and to high energy cosmic rays and neutrino astrophysics. There is also a special section devoted to the International Space Station and its scientific utilization.

This NATO Advanced Study Institute provided an up dated understanding, from a fundamental and deep point of view, of the progress and current problems in the early universe, cosmic microwave background radiation, large scale structure, dark matter problem, and the interplay between them. The focus was placed on the Cosmic Microwave Background Radiation. Emphasis was given to the mutual impact of fundamental physics and cosmology, both at theoretical and experimental-or observational-levels, within a deep and well defined programme, and a global unifying view, which, in addition, provides of careful inter-disciplinarity. Special Lectures were devoted to neutrinos in astrophysics and high energy astrophysics. In addition, each Course of this series, introduced and promoted topics or subjects, which, although not being of purely astrophysical or cosmological nature, were of relevant physical interest for astrophysics and cosmology. Deep understanding, clarification, synthesis, careful interdisciplinarity within a fundamental physics framework, werethe maingoals ofthe course. Lectures ranged from a motivation and pedagogical introduction for students and participants not directly working in the field to the latest developmentsand most recent results. All Lectures were plenary, had the same duration and were followed by a discussion. The Course brought together experimentalists and theoretical physicists, astrophysicists and astronomers from a variety of backgrounds, including young scientists at post-doctoral level, senior scientists and advanced graduatestudentsas well.

Advance Praise for The Accelerating Universe

""""The Accelerating Universe"" is not only an informative book about modern cosmology. It is rich storytelling and, above all, a celebration of the human mind in its quest for beauty in all things.""
--Alan Lightman, author of Einstein's Dreams

""This is a wonderfully lucid account of the extraordinary discoveries that have made the last years a golden period for observational cosmology. But Mario Livio has not only given the reader one clear explanation after another of what astronomers are up to, he has used them to construct a provocative argument for the importance of aesthetics in the development of science and for the inseparability of science, art, and culture.""
--Lee Smolin, author of ""The Life of the Cosmos""

""What a pleasure to read An exciting, simple account of the universe revealed by modern astronomy. Beautifully written, clearly presented, informed by scientific and philosophical insights.""
--John Bahcall, Institute for Advanced Study

""A book with charm, beauty, elegance, and importance. As authoritative a journey as can be taken through modern cosmology.""
--Allan Sandage, Observatories of the Carnegie Institution of Washington

Deep-sky observing - that's looking at the stars, nebulae and galaxies - is easily the most popular field for amateur astronomers. The big problem faced by non-professional observers is what to look at - what's visible at a paticular time of year. The Deep-sky Observer's Year is a month-by-month guide to the best objects to view. Objects are given a "star rating" according to how difficult they are to observe or image (i.e. photograph) with a particular size of telescope. The book includes many images produced by amateur astronomers, as well as photographs from NASA, ESA and ESO. There is also some background information about the objects that can be seen, along with lots of useful tips, hints, and resources (especially about what's available on the Internet) for deep-sky observers.

This textbook attempts to bridge the gap that exists between the two levels on which relativistic symmetry is usually presented - the level of introductory courses on mechanics and electrodynamics and the level of application in high energy physics and quantum field theory: in both cases, too many other topics are more important and hardly leave time for a deepening of the idea of relativistic symmetry. So after explaining the postulates that lead to the Lorentz transformation and after going through the main points special relativity has to make in classical mechanics and electrodynamics, the authors gradually lead the reader up to a more abstract point of view on relativistic symmetry - always illustrating it by physical examples - until finally motivating and developing Wigner's classification of the unitary irreducible representations of the inhomogeneous Lorentz group. Numerous historical and mathematical asides contribute to conceptual clarification.

Critical Acclaim for
PLANETARY DREAMS
The Quest To Discover Life Beyond Earth

"The stunning insights provided in Planetary Dreams make it a book for everyone who has the slightest curiosity about our role in the cosmos."——Hugh Downs, ABC News, 20/20

"The broadest and, in a philosophical sense, the deepest book to examine the question of the origins of life in the universe. . . . A wise, kindly, and beautifully written book, Planetary Dreams sets forth a vision of a truly human and humane future and a hope for a richly inhabited universe."——Ben Bova, six-time Hugo Award winner and past president of the National Space Society

"If you are interested in the search for extraterrestrial life. . .then Planetary Dreams is a must read. Delightfully written."——Louis D. Friedman, Executive Director, The Planetary Society

"Combining many narrative elements, including a description of his fanciful institution, the Museum of the Cosmos, Shapiro’s imaginative, multifaceted work should meet the yearnings of space enthusiasts and of the wider public, as Carl Sagan’s books did."——Booklist

Our true origins are not just human, or even terrestrial, but in fact cosmic. Drawing on recent scientific breakthroughs and the current cross-pollination among geology, biology, astrophysics, and cosmology, ?Origins? explains the soul-stirring leaps in our understanding of the cosmos. From the first image of a galaxy birth to Spirit Rover's exploration of Mars, to the discovery of water on one of Jupiter's moons, coauthors Neil deGrasse Tyson and Donald Goldsmith conduct a galvanizing tour of the cosmos with clarity and exuberance.

Topological defects formed at symmetry-breaking phase transitions play an important role in many different fields of physics. They appear in many condensed-matter systems at low temperature; examples include vortices in superfluid helium-4, a rich variety of defects in helium-3, quantized mag netic flux tubes in type-II superconductors, and disclination lines and other defects in liquid crystals. In cosmology, unified gauge theories of particle interactions suggest a sequence of phase transitions in the very early uni verse some of which may lead to defect formation. In astrophysics, defects play an important role in the dynamics of neutron stars. In 1997 the European Science Foundation started the scientific network "Topological defects" headed by Tom Kibble. This network has provided us with a unique opportunity of establishing a collaboration between the representatives of these very different branches of modern physics. The NATO-ASI (Advanced Study Institute), held in Les Houches in February 1999 thanks to the support of the Scientific Division of NATO, the European Science Foundation and the CNRS, represents a key event of this ESF network. It brought together participants from widely different fields, with diverse expertise and vocabulary, fostering the exchange of ideas. The lectures given by particle physicists, cosmologists and condensed matter physicists are the result of the fruitful collaborations established since 1997 between groups in several European countries and in the U.S.A."

The objects listed in the Caldwell Catalogue supplement Messier's famous catalogue of 110 non-stellar objects, and they include some of the most fascinating objects for amateur astronomers. This comprehensive guide to the Caldwell objects has been produced specially for observers. Each object is conveniently on a double-page spread (which can even be photocopied for field use). There is a photographic image of every object and full technical data including position (with the major Star Atlas chart numbers) and NGC number. It also includes a finder map showing TelradTM circles, a star-hopping guide, a visual description of what the object looks like through amateur telescopes, and a physical description of the object itself. There is a fold-out map showing the location of all the Caldwell objects in the sky. Every practical amateur astronomer will find this an essential guide to observing the Caldwell objects.

A discussion of the implications for philosophy of recent experimental results that confirm some counterintuitive aspects of the way matter behaves. The authors show that a generalised principle of complementarity is pervasive not only in physical theories such as cosmological models of the universe, but also in the construction of all human realities. They discuss in detail Bells inequalities for quantum mechanical measurements as well as recent experiments which imply that even remote parts of the universe are "entangled." They go on to suggest that consciousness can no longer be divorced from the way science operates, and conclude by claiming that this entails a new way of understanding the universe - one that could obviate much of the current conflict between science and religion while providing at the same time a basis for valuation that is better suited for co-ordinating all human experience. This second edition has been completely rewritten and brought up to date.

A complete account of the fundamental techniques of general relativity and their application to cosmology. The book includes reviews of the different cosmological models and their classification, including such topics as causality and horizons, the cosmological parameters, observational tests and constraints of cosmology, symmetries and the large scale topology of space and space-time, and the use of supernovas as cosmological indicators. The perturbations to the cosmological models are discussed throughout the volume. The cosmic microwave background is presented, with an emphasis in secondary distortions in relation to cosmological models and large scale structures. Recent results on dark matter are summarised. A general review of primordial nucleosynthesis is given. Gravitational lensing is discussed in great detail. Most contributions show a balance between theory and observation. Readership: A solid background for students and researchers intending to work in the field of theoretical and observational cosmology.

The 186th IAU Symposium came at an exciting and perhaps even historic time for extragalactic astronomy. New spacecraft observations plumbed the depths of the Universe out to redshifts of five, while revealing astounding details of nearby galaxies and AGN at intermediate redshifts. Theoretical ideas on structure formation, together with results from detailed numerical modeling, created a comprehensive framework for modeling the formation of galaxies and the transformation of galaxies by interactions and mergers. All these strands came together at the Symposium, as participants glimpsed a developing synthesis highlighting galactic encounters and their role in the history of the Universe. This volume offers professional astronomers, including PhD students, an overview of the rapidly advancing subject of galaxy interactions at low and high redshifts.

Did you know? . . .

• Russia’s October Revolution in 1917 actually occurred on November 7th
• For centuries, Britain and the colonies rang in the New Year on March 25th
• The Roman Empire originally observed an eight-day week
• The anno Domini (a.d.) year-counting system is wrong, and Jesus’ birth actually occurred some years before December 25, 1 b.c.

These are just a few of the little-known facts that you will find in acclaimed author Duncan Steel’s eye-opening chronicle of the evolution of the calendar, Marking Time: The Epic Quest to Invent the Perfect Calendar.

Steel takes you across the full span of recorded history, behind the seismic shifts within politics, religion, and science, and examines the ways in which people and events forged the calendar that we have today. Starting with Stonehenge and the first written records of the year and the day by the Sumerians around 3500 b.c., Marking Time charts the calendar’s ever-changing, erratic trajectory–from the Egyptians’ reliance on the star Sirius to the numbering of the years, linked to the celebration of Easter in Christian churches.

You will also gain insight into:

• The mystery of the missing ten days
• The Venerable Bede and the origins of the anno Domini dating system
• How and why comets have been used as clocks
• Julius Caesar’s 445-day-long Year of Confusion
• Why there is no year zero between 1 b.c. and 1 a.d.
• Whether the year 2100 should be a double-leap year

A provocative history lesson and a unique, entertaining read rolled into one, Marking Time will leave you with a sense of awe at the random, hit-or-miss nature of our calendar’s development–a quality that parallels the growth of civilization itself. What results is a truthful, and, above all, very human view of the calendar as we know it. After reading Marking Time, you will never look at the calendar the same way again.

What are the origins of the years, months, and days that give our lives their familiar rhythm?

In Marking Time: The Epic Quest to Invent the Perfect Calendar, astronomer and acclaimed author Duncan Steel marches through human history to deliver a fascinating, milestone-by-milestone look at how the modern-day calendar came to be. From the definition of the lunar month by Meton of Athens in 432 b.c., through present-day proposals to reform our calendar, Steel captures the often-flawed but always fascinating story of the calendar’s evolution.

Here, you will discover fun facts and surprising anecdotes as the author visits with some of the seminal figures of the past–Julius Caesar, William the Conqueror, and Benjamin Franklin among them–as well as some lesser-known names, all of whom left an indelible mark on how we record time. You will also gain an in-depth look at the role science, astronomy, religion, politics, and even war played in various calendrical systems, including the one hanging on your wall. Open up a copy of Marking Time and, as the author puts it, "read, puzzle, and enjoy."

"Guaranteed to satisfy the appetite of interested lay readers for all the facts. Gourmet reading!" – Library Journal on Steel’s Rogue Asteroids and Doomsday Comets

Distance determination - finding out how far away different astronomical objects are - is an essential and currently highly topical subject in astronomy. A great deal of progress has been made during the last part of the 20th century. Measuring the Universe provides a unified treatment of the various techniques used for distance determination. It begins by describing methods to measure distances on Earth then gradually climbs the "distance ladder" to enable us to estimate the distance to the farthest objects, ending with a discussion of particle horizons within an expanding and inflationary universe. Aimed at first-year undergraduates of astronomy and astrophysics, the book emphasises general physical principles rather than mathematical detail. The text is enhanced and complemented by the use of many worked examples, and questions and problem solving exercises at the end of each chapter.

How old is our Universe? At what speed is our Universe expanding? Is our universe flat or curved? How is the hierarchical structure of the present Universe formed? The purpose of IAU Symposium 183 on the Cosmological Parameters and the Evolution of the Universe was to encourage a state-of-the-art discussion and assessment of cosmology by putting together the latest observational data and theoretical ideas on the evolution of the universe and cosmological parameters. In this volume, excellent reviews on these subjects by distinguished scientists are included. The first article by M.S. Longair, `Cosmological Parameters and the Evolution of the Universe: Progress and Prospect', is a magnificent general review which can be understood by non-specialists. The other reviews include Hubble Constants (W.L. Freedman, G.A. Tammann), Microwave Background Radiation (R.B. Partridge, N. Sugiyama), Galaxy Formation and Evolution (R.S. Ellis) and Alternative Cosmological Models (J.V. Narlikar). In addition to the reviews, recent observational and theoretical developments by outstanding active scientists are included.

Transient phenomena are short-lived astronomical events, unusual in a science in which time is more often measured in millennia than milliseconds. There is a fascination with transient phenomena, predictable or otherwise, that astronomers of all abilities share. In Meteors, Comets, Supernovae, Neil Bone gives guidelines for observers, including the best possible periods (months or years) to see seasonal but unpredictable phenomena like meteors and sunspots. Recording such outbursts involves visual observing techniques, photography, and even the relatively new field of the video recording of meteors, which are also examined in detail. The book also includes material about phenomena that occur in the lower atmosphere (such as "ozone eaters", nacreous clouds, solar and lunar haloes), which although not strictly astronomical in their nature attract the attention of dedicated sky-watchers.

The Quest To Discover Life Beyond Earth.

"The 'dreams' that I write of are not the usual ones, the images that come up in our minds involuntarily during certain stages of sleep, but rather the hopes and expectations that we have lavished upon other worlds around us."—from the Preface.

The surprisingly long history of debate over extraterrestrial life is full of marvelous visions of what life "out there" might be like, as well as remarkable stories of alleged sightings and heated disputes about the probability that life might actually have arisen more than once. In Planetary Dreams, acclaimed author Robert Shapiro explores this rich history of dreams and debates in search of the best current answers to the most elusive and compelling of all questions: Are we alone?

In his pursuit, he presents three contrasting views regarding how life might have started: through Divine Creation, by a highly unlikely stroke of luck, or by the inevitable process of a natural law that he terms the Life Principle. We are treated to a lively fictional dinner debate among the leading proponents of these schools of thought—with the last named group arguing that life has almost surely formed in many places throughout the universe, and the others that life may well be entirely unique to our own blue planet. To set the stage for a deep exploration of the question, the author then leads us on a fantastic journey through the museum of the cosmos, an imagined building that holds models of the universe at different degrees of magnification. We then journey deep into inner space to view the astonishingly intricate life of a single cell, and learn why the origin of such a complex object from simple chemical mixtures poses one of the most profound enigmas known to science.

Writing in a wonderfully entertaining style, Shapiro then reviews the competing theories about the start of life on Earth, and suggests the debate may best be settled by finding signs of life on the other worlds of our solar system. He takes us on a guided tour of the most likely sites, from the underground hot springs of Mars to the ice-covered oceans of Jupiter's airless moons.

Along the way, he shares a wealth of fascinating stories about the ways in which our views of the heavens have changed, from the theories of ancient philosphers, who argued that the Moon was inhabited, to the current Origins and Astrobiology initiatives of NASA. He describes the probes that will be sent out in the near future in pursuit of the first compelling physical evidence of life beyond Earth, and concludes with a radical suggestion about how this quest might be supported through the next millennium. As we launch into an exciting new era of space exploration, Planetary Dreams offers a thoughtful and entertaining exploration of both the history of our hopes and expectations and a vision of a possible future in which the discovery of life elsewhere will provide a new view of our place in the universe.

This book provides a comprehensive, critical study of the oldest and most famous argument for the existence of God: the Cosmological Argument. Professor Rowe examines and interprets historically significant versions of the argument from Aquinas to Samuel Clarke and explores the major objections that have been advances against it. Beginning with analyses of the Cosmological Argument as expressed by Aquinas and Duns Scotus in the thirteenth century, the author seeks to uncover, clairfy , and critically explore the philosophical concepts and theses essential to the reasoning exhibited in the principal versions of the Cosmological Argument. The major focus of the book is on the form that the argument takes in the eighteenth century, principally in the writings of Samuel Clarke. The author concludes with a discussion of the extent to which the Cosmological Argument may provide a justification for the belief in God. In a new Preface, the author offers some updates on his own thinking as well as that of others who have grappled with this topic.

An analysis of one of the three great papers Einstein published in 1905, each of which was to alter forever the field it dealt with. The second of these papers, "On the Electrodynamics of Moving Bodies", established what Einstein sometimes referred to as the "so-called Theory of Relativity". Miller uses the paper to provide a window on the intense intellectual struggles of physicists in the first decade of the 20th century: the interplay between physical theory and empirical data; the fiercely held notions that could not be articulated clearly or verified experimentally; the great intellectual investment in existing theories, data, and interpretations - and associated intellectual inertia - and the drive to the long-sought-for unification of the sciences. Since its original publication, this book has become a standard reference and sourcebook for the history and philosophy of science; however, it can equally well serve as a text on twentieth-century philosophy.