The collapse of an investment mania usually reminds people that the phrase "This time is different" is dangerous. Recollections of this mantra then typically either state outright or at least imply that "It is never different." However, there is at least one counterexample to this cautious view,...

One of the most popular investment anecdotes relates how Isaac Newton, after cashing in some large early gains, staked his fortune on the success of the South Sea Company of 1720 and lost heavily in the ensuing crash. However, this tale is based on only a few scraps of hard evidence, some of...