Bibliography: p. 893-955. Includes index.

Introduction : how to write history of biology -- The place of biology in the sciences and its conceptual structure -- The changing intellectual milieu of biology. Diversity of life. Macrotaxonomy, the science of classifying -- Grouping according to common ancestry -- Microtaxonomy, the science of species. Evolution. Origins without evolution -- Evolution before Darwin -- Charles Darwin -- Darwin's evidence for evolution and common descent -- The causation of evolution : natural selection -- Diversity and synthesis of evolutionary thought -- Post-synthesis developments. Variation and its inheritance. Early theories and breeding experiments -- Germ cells, vehicles of heredity -- The nature of inheritance -- The flowering of Mendelian genetics -- Theories of the gene -- The chemical basis of inheritance. Epilogue : toward a science of science. Explores the development of the ideas of evolutionary biology, particularly as affected by the increasing understanding of genetics and of the chemical basis of inheritance.