Evolutionary Biology, of which this is the twenty-second volume, continues to offer its readers a wide range of original articles, reviews, and commentaries on evolution, in the broadest sense of that term. The topics of the reviews range from anthropology, molecular evolution, and paleobiology to principles of systematics. In recent volumes, a broad spectrum of articles have appeared on such subjects as asymmetric sexual isolation, biochemical systematics in plants, species selection, DNA hybridization and phylogenetics, modes of evolution in Pleistocene rodents, and development and...