The Many Lives of Herbert O. Yardley

A biography of Herbert Osborn Yardley written by employees of the National
Security Agency (NSA). Yardley was an unusual sort, initially self-taught as a
cryptologist and cryptanalyst, who during his long career worked for the U.S., China and Canada. At other times, he wrote books and magazine articles about cryptography, which eventually earned him disfavor with government authorities and resulted in new laws restricting disclosure of classified information.