Harris presents an ambitious and compelling thesis regarding the causes of and unconscious motivations behind the development of human societies ancient & modern.
He focuses on the cycle of depletion of resources, intensification, and decline as the most consistent story of humankind since the advent of agriculture. He argues that intensification is a natural reaction to a list of deplorable choices when societies are faced with threats to their way of life, but that intensification is always the wrong choice.
The parallels to our own modern ecological crisis are astounding, and the lessons Harris teaches should be heeded by all (especially those in privileged nations like the US).