The list is organized into evolution , biographies, and natural history/miscellany . 

Evolution in its various guises. 

• Stephen J. Gould's essay collections -- The Flamingo's Smile, Bully for Brontosaurus, Eight Little Piggies, The Dinosaur in the Haystack -- provide great discussions of every aspect of evolutionary biology under the sun. His style is a bit ornate and wide-ranging for some readers. 
• Richard Dawkins has written an excellent set of books -- including The Selfish Gene, The Blind Watchmaker, The Extended Phenotype, A River Out Of Eden, and Climbing Mount Improbable -- addressing many of the same topics as Gould, but from a very different perspective. Some will find Dawkins' style easier to follow than Gould's. I recommend Mt. Improbable in particular. 
• The Beak of theFinch, by Johnathan Weiner, discusses evolutionary theory relating to natural selection and speciation by presenting the pioneering work of Peter and Rosemary Grant have done over the last 30 years or so on the finches of the Galapagos Islands. Fantastic! 
• Extinction: Bad Genes or Bad Luck?, by David Raup, explains some of the mysteries of the process that has eliminated 99% of all the species of organisms that have ever lived and provides his views on the relationship(s) between "normal" and "mass" extinction events. 
• The Miner's Canary, by Niles Eldredge, addresses much the same topic, with a distinct conservation bent. I found Raup's book to be the more useful of the two, for what that's worth. 
• Ancestors,by Johansen, Johansen, and Edgar, is the companion book to a PBS video series and offers a good overview of human evolution, with particular attention to the relationships among various hominids and at least a brief evaluation of various competing hypotheses about human evolution. Remember that this whole field is still rife with controversy! 
• The Third Chimpanzee, by Jared Diamond, is an admittedly more speculative work focusing on the specific evolutionary " forces" (natural selection, sexual selection, genetic drift) shaping human evolution since our divergence from our nearest primate relatives.

• Apes, Angels and Victorians: Darwin, Huxley and Evolution by William Irvine is pretty much what the title says -- a combined biography of Darwin and his "bulldog", with special attention to events surrounding the publication of The Origin. 
• Darwin: The Life of a Tormented Evolutionist is the latest, and by at least some accounts, best of the Darwin biographies. Adrian Desmond and James Moore draw extensively on original journals and other documents to recreate, as much as possible, Darwin's own thinking about his work. 
• The Kindly Fruits of the Earth: Recollections of an Embryo Ecologist is the autobiography of the formative years of G. Evelyn Hutchinson, one of the most importante cologists of this century. 
• Naturalist is Edward O. Wilson's account of his development as an entomologist and ecologist, as the father of sociobiology, and a major proponent of thev alue and importance of conserving biodiversity. 
• Woman in the Mists, by Farley Mowat, tells the story of gorilla researcher Dian Fossey. 
• A Feeling for the Organism is Evelyn Fox Keller's wonderful biography of Barbara McClintock, 1983 Nobel Laureate whose work on transposons was an early harbinger of the age of molecular genetics. 
• Green Laurels ,by Donald Culross Peattie offers brief discussions of the lives and works of great naturalists from middle ages through the publication of The Origin. 
• Men of Science in America, by Bernard Jaffee, also offers vignettes of key scientists-- including Thomas Say, O.C. Marsh, and T. H. Morgan -- up to the late1800's. 
• Impressions of Great Naturalists , by Henry Fairfield Osborn, is yet another collection of biographical "reminiscences" of such naturalists as Darwin, Roosevelt, John Burroughs, and John Muir, told by the former president of the American Museum of Natural History. 
• Concessions to the improbable: an unconventional autobiography  is George Gaylord Simpson's delightful description of his life, travels, and work.
• Ancestral Passions is science writer Virginia Morrell's biography of the Leakey family (Louis, Mary, Richard et al.) and their pioneering work unravelling human evolutionary history.  Amazing!

• Through a Window: My Thirty Years With The Chimpanzees of Gombe is Jane Goodall's latest discussion of the fascinating lives of our nearest living relatives. 
• The Diversity of Life offers E. O. Wilson at his most eloquent, interesting, and passionate as he describes the processes and events that have shaped the diversity of life on earth, those that currently threaten its existence,and the new ethic he proposes as necessary if we are to maintain that diversity and a quality of life worth living. 
• The Growth of Biological Thought and Toward a New Philosophy of Biology are (respectively) Ernst Mayr's history of seminal ideas in biology and a broader discussion of the philosophical underpinnings of modern evolutionary biology. 
• The Song of the Dodo, by David Quammen, is an excellent combination of natural history, island biogeography, and conservation