The centerpiece of this collection of essays on evolution published at different times in Eiseley's life is the title work, an essay devoted to resurrecting the name and importance of Edward Blyth, a 19th-century naturalist. Eiseley credits Blyth with the development of the idea, and even the coining of the words ""natural selection,"" which Darwin absorbed and enlarged upon. Blyth was no evolutionist, however, and also was a strict believer. His ideas of natural selection focused on the conserving power of selection--the envirionmental influences and sexual selection processes favorable to perpetuation of the general type of the species. As Eiseley points out, it was Darwin's genius to see the other side of the coin of natural selection--that it could serve as the force for change and the development of new species over time. The evidence that Darwin had read and indeed corresponded with Blyth is abundant, as Eiseley's scholarly sleuthing demonstrates. Why, then, do we not hear of Blyth as we do of Wallace, Lyell, Erasmus, Darwin, Malthus, and others whom Darwin acknowledges as mentors or co-developers of evolutionary theory? Eiseley takes to task assorted apologists and Darwin biographers who, in parallel with studies of Coleridge, attribute Darwin's lapses to the theory of ""unconscious creation."" Eiseley writes off that romantic notion even with reference to Coleridge himself, and argues more mundanely that it probably would have gone against the grain for Darwin to credit a source who did not himself espouse a belief in evolution. Included in the volume are brief, insightful portraits of Darwin, Lyell, and Wallace; Blyth's relevant papers; essays on the impact of the discovery of the first fossil cranium--Neanderthal man--prior to the publication of the Origin of Species; some thoughts on Darwin's Descent of Man; and a concluding speculation on the meaning of evolution. The last piece is very much Eiseley's poetic from-whence-do-we come/whither-do-we-go vein. In contrast, the other essays are straightforward scholarly expositions which reveal an intelligence and sensitivity to 19th-century society and the personalities that shaped the history of science.