This book is intended as a text for a course in programming languages. The pre requisites for such a course are insight in structured programming and knowledge as well as practical experience of at least one (e.g., Pascal) of the programming languages treated in the book. The emphasis is on language concepts rather than on syntactic details. The book covers a number of important language concepts that are related to data struc tures. The comparison of the programming languages Pascal, Algol 68, PL/1 and Ada consists in investigating how these concepts are supported by each of these languages. Interesting evaluation criteria are generality, simplicity, safety, readability and portability. The study of programming languages is based on a simple model called SMALL. This model serves as a didactic vehicle for describing, comparing and evaluating data structures in various programming languages. Each chapter centers around a specific language concept. It consists of a general discussion followed by a number of language sections, one for each of the languages Pascal, Algol 68, PL/1 and Ada. Each of these sections contains a number of illustrating program fragments written in the programming language concerned. For each program fragment in one language, there is an analogous fragment in the others. The book can be read "vertically" so that the programming languages Pascal, Algol 68, PL/1 and Ada are encountered in that order several times. A "horizontal" reading of the book would consist in selecting only those sections which only concern one language."

"I prefer to view formal methods as tools. the use of which might be helpful." E. W. Dijkstra Algebraic specifications are about to be accepted by industry. Many projects in which algebraic specifications have been used as a design tool have been carried out. What prevents algebraic specifications from breaking through is the absence of introductory descriptions and tools supporting the construction of algebraic specifications. On the one hand. interest from industry will stimulate people to make introductions and tools. whereas on the other hand the existence of introductions and tools will stimulate industry to use algebraic specifications. This book should be seen as a contribution towards creating this virtuous circle. The book will be of interest to software designers and programmers. It can also be used as material for an introductory course on algebraic specifications and software engineering at undergraduate or graduate level. Nowadays. there is general agreement that in large software projects appropriate specifications are a must in order to obtain quality software. Informal specifications alone are certainly not appropriate because they are incomplete. inconsistent. inaccurate and ambiguous and they rapidly become bulky and therefore useless. The only way to overcome this problem is to use formal specifications. An important remark here is that a specification formalism (language) alone is not sufficient. What is also needed is a design method to write specifications in that formalism.

Critics claimed that Poetry for the Now, first published in 2009, was perhaps the most complete work of art ever set before human eyes. Upon its release, the rocking and swaying of the turbulent world calmed, and a passive and forlorn population suddenly brightened in demeanor collectively for the first time in human history. There was almost certainly no need for a second volume. But if one believes that human nature has a limited potential for understanding, love, and vitality, then this person is clearly an enemy of mankind and must be thrown into a pit of snakes. Poetry for the Now 2, previously thought to be superfluous, has boomed itself onto the stage and merely by its presence has already proven to be the catalyst for the next stage in human evolution. Let the curtains rise! Let the trumpets sound! Open your outer and inner ears, and let the triumph of perfect poetry buoy you to untold states of being!

Too often is poetry simply the product of man struggling to come to grips with the world around him. He begs, he pleads, he yearns for understanding. And too often it does not come.

Not so here. Johan Lewis, a prodigal genius for his time, has unleashed the new power that is the written word. With astonishing prowess and insatiable word-play, Mr. Lewis embarks on a journey to not only question man's ultimate plight, but eventually, find the answer to it.

As gripping as it is audacious. As shrewd as it is page-turning. Soul-charging, sexual, electrifying, and yet timbered with a pang of heart-felt honesty. These are surely to be the best words you've ever read.