Four theoretical monographs, written by biologists in the wake of the sociobiology debate, and which treat, or purport to treat, the topic of sociocultural evolution are examined in this paper. On the biosocial spectrum they range from Trivers' pure sociobiology, to Lumsden and Wilson's sociobiology "in drag," to Boyd and Richerson's genuinely dual approach, to Cavalli-Sforza and Feldman's purely cultural transmission and evolution. The latter is likely to prove of greatest interest to social scientists and represents a major advance in (...) theorizing mathematically about social change. While the most comprehensive, Boyd and Richerson's "dual inheritance" model ultimately places more emphasis on the biological evolution of the capacity for culture than on genuine gene/culture coevolution even though it is conceivable that cultural transmission and evolution could be providing the selective force responsible for some fundamental biological phenomena such as sexual reproduction in long-lived vertebrates for example. The relationship between contemporary evolutionary and non-evolutionary theories of social change is not dealt with here but the former are very relevant to the latter because evolutionists believe they have available sophisticated solutions to problems which continue to plague other theoretical traditions. (shrink)