"Memoirs of Extraordinary Popular Delusions — Volume 1" by Charles Mackay is a study of crowd psychology first published in 1841. This journalistic exploration examines how entire societies fall prey to irrational beliefs and financial manias. Mackay investigates economic bubbles like the South Sea Company and Dutch tulip mania, alongside witch trials, alchemy, the Crusades, and countless other collective obsessions. Through colorful anecdotes and debunking analysis, he reveals how crowds abandon reason and embrace delusion, offering timeless lessons about human behavior that continue influencing financial thinkers today. (This is an automatically generated summary.)