In Power and Privilege, Gerhard Lenski's theory of the evolution of systems of inequality, he showed some recognition of gender inequality but, as universally accepted in sociology at the time, “social” stratification was conceptualized implicitly as inequality between male household heads. To move from this to explaining gender inequality requires consideration of constructs in addition to those developed by Lenski, but in terms of his typology of societies based on technology and size of economic surplus, the level of gender stratification tracks that of “social” stratification and the basic variables he delineates remain centrally important.