Popular delusion history and crowd psychology

Extraordinary Popular Delusions and the Madness of Crowds

A classic historical survey of popular delusions, economic bubbles, and social manias. Mackay explores the psychology behind mass hysterias, including the South Sea Bubble, the Mississippi Scheme, and 'Tulipomania'. Significantly for this collection, he provides extensive chapters on the history of the witch-hunts, the crusades, and the search for the philosopher's stone (alchemy), treating them as irrational collective delusions. It is a foundational work of social psychology and skepticism.