Niles Eldredge, a curator in the Department of Invertebrates at the American Museum of Natural History, may be best known as the coauthor of the concept of "punctuated equilibria". Here Eldredge explores how the physical forces shaping our world relate to the process of biological evolution in the context of the history of ideas on evolution. Praised by Ian Tattersall for "weaving together an extraordinary diversity of information into a single coherent theory of the evolution of the biosphere" and as "smoothly flowing and highly readable". The humorous and thought-provoking opening pages are online at www.whfreeman.com