"Prices on the New York Stock Exchange are affected by French politics, German banking conditions, wars and rumors of war in the Near East, the Chinese money market, the condition of the wheat crop in the Argentine, the temper of the Mexican Congress, as well as by a host of domestic influences."

-- Philip Carret, The Art of Speculation, 1931

I thought this was interesting.
The above was written in 1931 duriing the depression.
Has anything changed as far as speculation or investing since then? No.
There is nothing new under the sun when it comes to people. They make the markets.