Herbert Yardley
Founder of America's first peacetime codebreaking bureau, who responded to its closure by writing a bestseller about everything it had done.
Born in 1889, Yardley was a State Department telegraph clerk when the First World War put him in charge of the Army's cipher section, MI-8. After the war the operation carried on secretly in New York as the Cipher Bureau — the Black Chamber — funded jointly by the Army and the State Department. Its finest hour came at the Washington Naval Conference of 1921–22, when it read Japan's diplomatic cables and knew exactly how far Tokyo would bend on fleet ratios.
In 1929 Secretary of State Henry Stimson cut the funding, reasoning that gentlemen do not read each other's mail. Out of work, Yardley published The American Black Chamber in 1931. Japan changed its codes and Congress passed a law against disclosing diplomatic ciphers. Friedman never forgave him. Yardley later worked in China and Canada, and his most enduring book turned out to be The Education of a Poker Player.