This volume presents a systematic discussion about the reasons for a culture making a transition from egalitarian hunter-gatherer to hierarchically based states as population density increases. According to the author, humans shifted from a low-carbohydrate diet largely based on hunter-gatherer sources to a high-carbohydrate diet largely based on agricultural when intensive agriculture began. He maintains that this diet change resulted in more body fat, which for females led to earlier menarche and a smaller reduction in fertility from nursing infants, which then led to shorter periods between pregnancies. He discusses the development of pork as a taboo food in ancient Israelite society and also the cow as a sacred animal and taboo food in Hindu culture. He also examines the concept of the hydraulic empire, ancient civilizations such as China, Persia, and Egypt that were reliant on water for agriculture.