One feature of Lenski's work that has won fairly wide acceptance among sociologists, as reflected in its incorporation into leading introductory textbooks in the discipline, is his ecological and evolutionary typology of human societies first proposed in "Power and Privilege" and enhanced later in "Human Societies" and other publications This typology is based on a combination of two elements: (1) the kind of environment to which the society must adapt, and (2) its level of technological development. In its most basic form, Lenski identifies seven types of societies: