For generations, the Dutch tulip craze of the 1630s has served as the textbook example of a speculative bubble. In the familiar version, ordinary families sold their homes to buy single bulbs, prices collapsed early in 1637, and much of the country was left in ruin. Much of that version comes from one source: a popular book on crowd behavior published by the Scottish writer Charles Mackay in 1841.
Mackay was writing two centuries after the events, and he relied heavily on pamphlets printed at the time of the crash. Those pamphlets, however, were largely moral satire, written to mock greed rather than to record it. When the historian Anne Goldgar examined contracts, court records and letters from the period, she found a far smaller story. The trade in rare bulbs was concentrated among fairly wealthy merchants and craftsmen. Prices did fall sharply, and many contracts were never honored, but she could not identify a single bankruptcy caused by the collapse.
None of this means that prices were never extraordinary; some bulbs did change hands for sums that would have bought a house. What changes is how the episode should be used. A story repeated for its lesson, rather than checked against its sources, can end up teaching the wrong one.
What is the passage mainly about?