Herbert Yardley

Herbert Osborn Yardley (April 13, 1889 – August 7, 1958) was an American cryptologist. He founded and led the Black Chamber, the US government's first peacetime cryptanalytic organization. Under Yardley, the cryptanalysts of the Black Chamber broke Japanese diplomatic codes and were able to furnish American negotiators with significant information during the Washington Naval Conference of 1921–1922.

He was a Recipient of the Distinguished Service Medal. In 1931 Yardley wrote the book The American Black Chamber about his experiences there. He later helped the Nationalists in China (1938–1940) to break Japanese codes. Following his work in China, Yardley worked briefly for the Canadian government, helping it set up a cryptological section (Examination Unit) of the National Research Council of Canada from June to December 1941. Yardley was reportedly let go due to pressure either from the Secretary of War Henry L. Stimson or from the British.