He attempts to answer the question why religion developed at all, relying on the challenging premises of cultural ecology, which holds that ecological factors such as environment, reproduction, survival, and the use of energy sources affect human behaviour and cultural institutions. He also argues that basic religious behaviours of the past and present have been shaped by our innate emotional make up, specifically our ability to enter into ecstatic states through a variety of techniques and to create binding relationships with other people or institutions or ideals associated with those states. The work concludes with a brief overview of contemporary industrial society from a cultural ecological perspective and broadly examines contemporary religious developments and possible future trends.