As the title aptly states this book deals with the magnificent second law of thermodynamics, to wit: an experimentally accessible quantity, entropy is a measure of chaos, and characterizes by its increase the direction of spontaneous physical and chemical change. Atkins states in his opening sentence, "No other part of science has contributed as much to the liberation of the human spirit as the second law of thermodynamics." The law is universal, admits of no macroscopically observable exceptions, and is of overwhelming importance in the understanding of nature and technology. Famously recondite and inherently mathematical, here the second law and entropy are luminously explicated through combined use of the written word and many extraordinarily effective images

. As the author intends, "any persistent reader, however science unprepared," will indeed be capable of mastering the book, but the greatest benefits will go to those readers professionally interested in the concept of entropy. Here one includes students of thermodynamics, from any of the relevant disciplines, e.g., physics, chemistry, biology, medicine, and engineering. The author apologizes to the scientifically informed for the "slowness of pace" used to develop the concept of entropy and its consequences, but such rhetorical politeness is unnecessary. The better informed the reader, the more this book will be appreciated for its coherent explanations and illustrations of such a vast subject. Professors teaching the concept of entropy will find themselves using the book's examples and graphical illustrations to buttress their own lectures. The book's reasonable price suits it well as assigned supplementary reading for enhanced appreciation of entropy.

A good historical account is given of how an analysis of the steam engine gave rise to a statement of the second law. Sadi Carnot "took the view that the operation of a steam engine was akin to the operation of a water mill, that caloric ran from the boiler to the condenser, and drove the shafts of industry as it ran, exactly as water runs and drives a mill." Subsequently an interpretation of entropy from a microscopic viewpoint was obtained. The famous equation of Boltzmann--one of the few in the book--defining entropy as S = k log W, relates it to W, the probability of a microscopic configuration. (The constant of proportionality, k, is Boltzmann's constant). A Carnot cycle analysis of an internal combustion engine is given, with particular emphasis upon types named after Sterling and Diesel. It is shown that any engine converting heat into work is limited to less than 100% efficiency, the exact efficiency being fixed by a quantity depending upon the temperature difference between heat reservoirs used for supplying heat to and expelling heat from an engine. A major advance in understanding followed from the work of Willard Gibbs, who showed how nature's tendency toward an overall increase in chaos provides a criterion to predict the natural direction of flow of all chemical reactions. The chemical reactions that underlie and sustain biological life also conform to the second law.

A most interesting discussion illustrates how the drive toward increased chaos leads paradoxically to local structures in space and time of great complexity and stability, including those characteristic of life. In this regard Atkins says:

Thus, we see that the tendency to chaos builds both the quaternary and the tertiary structures of proteins, for the ordered helices bend and buckle, and the surroundings become more disorganized. It also builds their secondary structures, for it is through the consequences for entropy that the hydrogen bonds, on which the structure depends, are locked into stability, and wind the ordered helix from the random chain of links. But what of the primary structure, the ordering of the amino acids themselves into the original chain? . . . can this essential primary step also emerge as a consequence of chaos?

Atkins has a deep understanding of the second law and imparts that to his reader. In another of his many excellent books, I he gives an equally good exposition of the second law, but there as is standard in such a textbook, the treatment is mathematical. The wonder of this book, The Second Law is the highly successful manner in which entropy and its consequences are conveyed, without the scaffolding of mathematics. In a deeply satisfying way, using sophisticated graphical representations and lucid companion explanations, Atkins succeeds in imparting a qualitative and intuitive appreciation of entropy. For those already familiar with the quantitative and mathematical development, the book has the effect of expanding and rounding one's appreciation of the subject. Thus, a great strength of the book is the beauty of exposition brought to such an important subject as entropy for the benefit, at many levels, of a wide-ranging audience.

A brief five-page appendix gives a nice summary of thermodynamics and of entropy developed from a mathematical point of view. In two pages are given a critique of and suggestions for further reading on the subject of the book.

For the sake of completeness, one may point out that a small number of technical errors have occurred in producing the book. For example, on page 203, the units of k are given as [M01^-1], instead of the intended [Joules per degrees Kelvin].

Finally, one mentions in passing, the author may be unnecessarily pessimistic, where he seems to conclude there is a lack of meaning and purpose in the world, apparently because all spontaneous activity ultimately is driven by a general increase in chaos. Thus, we read in the concluding remarks, ". . . we may sometimes have been deluded into ascribing to our own and others' existence a purpose, and we may have left, to a greater or lesser degree (depending on the opportunities inherited from chance), a lemming's spoor across the history of the world," and in a similar vein,

We are the children of chaos, and the deep structure of change is decay. At root, there is only corruption, and the unstemmable tide of chaos. Gone is purpose; all that is left is direction. This is the bleakness we have to accept as we peer deeply and dispassionately into the heart of the Universe. Yet, when we look around and see beauty, when we look within and experience consciousness, and when we participate in the delights of life, we know in our hearts that the heart of the Universe is richer by far. But that is sentiment, and is not what we should know in our minds . . . .