This is the best popular book on chaos, dynamic systems, and entropy that I have ever read, by one of the pioneers of this field. I have remarked in my reviews of Gribbin, Kaku, and others that Creative Geniuses in science (unlike Ingenious Followers who are so abundant) inspire others and themselves often by popularizing science in ordinary English. It is a good sign if they do this often, but sometimes they only do it seldom or never. Ruelle, as far as I know, only did it once, in this book, and the reader who loses the opportunity to obtain this book has lost a classic. Ruelle inspired me at an important place in my career (my fields are related to the probability-logic-entropy-physics interface). I am especially fond of recalling his description of how extremely new creations or inventions are typically received in science: journal reviewers will usually contradict each other in their haste to oust the newcomer. There are still journals which do not touch chaos, entropy, dynamic systems, fractals, not to mention my own field of logic-based probability.