Excellent book. The high point for me was the enterprising fellow who set up a stall in London during the South Sea Bubble (the original bubble!), allowing people to invest in "An undertaking of great advantage, but nobody to know what it is." People lined up for a couple of days to give the fellow their money...after which the fellow disappeared, never to be seen again. No lies detected!

This is a fun book, but it famously embellishes, exaggerates, and sensationalizes the tulip bubble [1]. The efficient markets people obviously don't like the story, but there doesn't seem to be much evidence that it happened on the same scale that Mackay portrays it.

[1] https://en.wikipedia.org/wiki/Tulip_mania#Modern_views

Along similar lines, the economist John Kenneth Galbraith has a book on financial bubbles and irrational crowd mentalities in financial market over the centuries: A Short History of Financial Euphoria [1]. Short, approachable, and interesting.

[1] https://www.goodreads.com/en/book/show/270746.A_Short_Histor...

My intro to psychology classes was one of the most valuable classes I ever took, just with the way it systematically shattered my own notion of how much I could trust my own notions of perception and thought to be a rational and accurate reflection of reality. I definitely had a notion of how irrational “people” could be before that, but of course I somehow thought I was above all that.

Supposedly investors are leveraging/borrowing money to buy into AI stocks right now...

People have been people since there have been people.

Interestingly, Charles Mackay, the author of Extraordinary Popular Delusions and the Madness of Crowds, was himself one of the most ardent cheerleaders for the Railway Mania [0] "urging people to put their money into the railways and pooh-poohing those who were concerned." and "He had become famous by mocking the bubbles of the past - but had rather less to say about the far more serious bubble that he himself had helped to inflate."[1]

[0] https://papers.ssrn.com/sol3/papers.cfm?abstract_id=1927396

[1] https://www.bbc.com/news/business-51311368

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