Book reviewed in this article:The Individual in Darwin's World, by S. J. Gould.The Units of Evolution. Essays on the Nature of Species, edited by M; Ereshefsky.Evolutionary Biology of Aging, by M. R. RoseGenetic and Ecological Diversity, by L. M. Cook.Evolutionary Genetics and Environmental Stress, by A. A. Hoffmann and P. A. Parsons.Sodium Hunger, by J. Schulkin.Practical Taxonomic Computing, by R. J. Pankhurst.