Longtime correspondent Ishabaka recently shared key takeaways from a classic on-the-ground account of The Great Depression in the U.S.:, The Great Depression, a Diary.

Another reader reminded me that The Great Depression was global, and occurred earlier that 1929 in other nations and had equally (or even more) calamitous consequences elsewhere. That said, humans are running Wetware 1.0 everywhere, so it's likely that many of these lessons are applicable to the collapse of speculative asset bubbles in other economies and eras--for instance, the global economy's Everything Bubble of 2023.

Here are Ishabaka's key takeaways from the book:

Mr. Roth was a lawyer in Youngstown, Ohio - a steel mill town, and near Weirton, West Virginia where I worked for two years.

He kept a diary from 1929 through the entire Depression. He seems an intelligent guy who sort of drove himself crazy trying to figure out economics and investment timing.

Some of the lessons are timeless:

1. Diversify - in the USA, people who held stocks and real estate were wiped out, while people who held Treasury bonds did great. In Germany, people who held government bonds were wiped out, while people who held real estate did great - especially if they had a mortgage. He relates the story of one American client who owned a piece of property in Germany with a $5,000 mortgage, which he was able to pay off with US $18 when hyperinflation hit Germany.

2. Have some cash - the biggest problem in general was lack of actual money - nobody had any, for anything. Over and over Roth laments having no cash to buy stock or real estate bargains in '32 and '33.

3. People never learn - In 1936, the Depression seems to be over and the stock market is booming. The same people who were wiped out in the crash of '29 are investing like crazy again - the US stock market crashed 50% the next year, 1937.