The 1841 Classic on Manias That Still Explains Every Tech Bubble

Charles Mackay’s “Memoirs of Extraordinary Popular Delusions and the Madness of Crowds,” now free on Project Gutenberg, is one of the earliest works on crowd psychology. First published in 1841, it catalogs how groups talk themselves into collective irrationality — financial bubbles like Dutch tulip mania, but also witch hunts, alchemy, religious crusades, and fads as trivial as beard fashions shaped by politics.

The book’s durability comes from its core insight: speculative manias follow a recognizable pattern of euphoria, herd behavior, and eventual collapse. That framework has made it a perennial reference for investors trying to spot the next crash, and it reads as uncannily relevant against modern episodes of speculative excess.

For a technical audience, the appeal is the pattern-matching. The dynamics Mackay described in 17th-century markets map cleanly onto crypto runups, meme stocks, and the current wave of AI hype — a reminder that the failure mode is human coordination, not the specific technology driving the frenzy.