Christopher Booker's book Groupthink: A Study in Self-Delusion and it explores the phenomenon of "groupthink," which is a psychological condition in which a group of people make irrational decisions because they are overly concerned with maintaining consensus and avoid any dissenting opinions. Booker examines numerous historical examples of groupthink, such as the French Revolution, the rise of Communism in Russia, the Nazi regime in Germany, and the climate change movement, arguing that these examples all demonstrate how groupthink can lead to disastrous consequences. He also discusses how groupthink manifests itself in contemporary Western society, including the rise of political correctness and the "cancel culture" movement.