Do gentlemen read each other's mail? Henry L. Stimson thought not. On the orders of Stimson, President Herbert Hoover's Secretary of State, the Cipher Bureau closed its doors in 1929. Herbert O. Yardley had established the office to decipher the coded communications of other countries. The work led to the arrest of German agents operating in the United States during the first World War. After his office closed, Yardley published the sensational book The American Black Chamber in 1931, giving a controversial look into American intelligence capabilities.
Yardley's only other successful book also involves a skills of probability and secrecy.
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