Extraordinary Popular Delusions and The Madness of Crowds - Charles Mackay

You are, I'm sure, dear reader, a sensible person, just like me. Left to ourselves, we think about things clearly, come to considered conclusions and act rationally. You would not, I'm sure, pay more for a tulip bulb than for a house, denounce your neighbour as a witch and only believe in her innocence if she drowned when thrown in the pond, or leave your family for years to rush off on Crusade just because some mad hermit preached at you. Neither, I like to think, would I. Yet people, apparently no stupider than we are, have done all these things, and done them not as isolated individuals, but in droves. Left to ourselves, we think about things ...