Agriculture is not crop production as popular belief holds - it's the production of food and fiber from the world's land and waters. Without agriculture it is not possible to have a city, stock market, banks, university, church or army. Agriculture is the foundation of civilization and any stable economy.
Normally I would not recommend a book that tells you how to make money in the stock market. Most of these books are aimed at gullible folk, and they usually make much more money for their authors than they do for the investing public.
Some calamities - the 1929 stock market crash, Pearl Harbor, 9/11 - have come like summer lightning, as bolts from the blue. The looming crisis of America's Ponzi entitlement structure is different. Driven by the demographics of an aging population, its causes, timing and scope are known.
I never attempt to make money on the stock market. I buy on the assumption that they could close the market the next day and not reopen it for five years.
The stock market has an insidious effect on C.E.O.s' moods, because of its impact not just on their companies but on their own bank accounts.