"Collapse" is an exploration of why certain societies throughout history have thrived while others have deteriorated and collapsed. The book delves into environmental problems, climate change, rapid population growth, and unwise political decisions as factors that contribute to the downfall of a civilization. The author uses examples from history such as the Mayans, the Vikings in Greenland, and modern examples like Rwanda and Haiti, to illustrate his points. It serves as both a historical analysis and a warning for modern societies to learn from the past in order to avoid a similar fate.

This book delves into the historical patterns of inequality, arguing that significant reductions in inequality have only ever been brought about by cataclysmic events, which the author terms as the "Four Horsemen": war, revolution, state collapse, and plague. Through a comprehensive examination of societal structures from the Stone Age to the modern era, it presents a compelling case that peaceful reforms have rarely led to lasting decreases in inequality. The work challenges readers to confront the uncomfortable reality that significant improvements in equality have often been forged in the crucible of immense human suffering, thereby questioning the prospects for achieving future equality without such extreme catalysts.