In "Extraordinary Popular Delusions and the Madness of Crowds" by Charles Mackay, the author delves into the psychological and sociological phenomena behind groupthink and mass hysteria. Published in 1841, Mackay's work explores various examples throughout history where individuals have succumbed to irrational beliefs and behaviors en masse. His writing style is both engaging and insightful, blending historical anecdotes with psychological analysis to provide a comprehensive examination of how human nature can lead to collective delusions. The book is considered a classic in the study of crowd psychology and remains relevant in understanding contemporary events like financial bubbles and social phenomena. Charles Mackay's thorough research and keen observations make this book a compelling read for anyone interested in the impact of group dynamics on individual behavior. His background as a journalist and poet likely influenced his ability to craft a well-rounded and thought-provoking exploration of the madness that can overtake societies.