When Harriman House announced the publication of the “definitive edition” of Charles Mackay’s Extraordinary Popular Delusions and the Madness of Crowds, I wondered what made it stand out from all the other editions of this classic work. I don’t have the definitive answer myself, but I can say that, unlike many other versions, this one is complete. It contains not just the first three chapters, the ones dealing most directly with markets, but the full 15 chapters. Thus you can learn not only about money mania, the South-Sea bubble, and tulipomania, but about, among other things, modern prophecies, the influence of politics and religion on the hair and beard, the witch mania, haunted houses, popular admiration of great thieves, and duels and ordeals.