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Herbert O. Yardley Collection

The National Security Agency’s latest declassification release consists of over 200 documents created by or about Herbert O. Yardley from between 1918 and 1968 (excluding 1924-1927). Many documents relate to Yardley’s years at MI-8, Military Intelligence’s wartime cryptologic section. Of special interest are documents from 1968 about NSA efforts to investigate claims that Yardley had been working for the Japanese.

Yardley headed MI-8 during World War I, and the Cipher Bureau (a.k.a. the Black Chamber) for several years following the war, excelling at breaking Japanese diplomatic messages. On October 31, 1929, the Cipher Bureau closed because of changing governmental priorities and policies. Desperately in need of money, Yardley resorted to writing a tell-all book, The American Black Chamber, which seriously affected communications security for many nations worldwide—including the United States. He would consequently live the rest of his life defending his actions and working as a cryptologic mercenary for whoever would hire him.

These documents enable a more nuanced view of a man otherwise noted for self-promotion and antiquated thinking. For example, through these documents, we learned that he was more aggressive in applying technology to his craft than otherwise believed. NSA is pleased to make this latest release available to the public.
ImageTitleDescriptionPublication NumberPublication Date
 1918 Herbert Yardley - F. W. Allen Correspondence Related to Operations of MI-8, 1918 April-DecemberHerbert O. Yardley Document Collection66658279/6/2019
 ACHIEVEMENTS OF THE CIPHER BUREAU (MI-8) DURING THE FIRST WORLD WAR, BY YARDLEY, 25 MAY 1945Herbert O. Yardley Document Collection66512879/6/2019
 CORRESPONDENCE FROM LOCKE ON MEXICAN CIPHER MESSAGE, 3 NOVEMBER 1922Herbert O. Yardley Document Collection66472969/6/2019
 CORRESPONDENCE MOORMAN FROM MEETH, 28 APRIL 1922Herbert O. Yardley Document Collection66471569/5/2019
 CORRESPONDENCE TO A-F FROM UNKNOWN, 6 SEPTEMBER 1928Herbert O. Yardley Document Collection66491649/6/2019
 CORRESPONDENCE TO AND FROM MEETH AND MOORMAN, 10-11 APRIL 1922Herbert O. Yardley Document Collection66471469/5/2019
 CORRESPONDENCE TO AND FROM MEETH AND MOORMAN, 2-3 MAY 1922Herbert O. Yardley Document Collection66471609/5/2019
 CORRESPONDENCE TO AND FROM MOORMAN AND MEETH, 22 MARCH 1922Herbert O. Yardley Document Collection66471329/5/2019
 CORRESPONDENCE TO AND FROM YARDLEY AND MILLIKEN, 18 MAY 1927Herbert O. Yardley Document Collection66491289/6/2019
 CORRESPONDENCE TO AND FROM YARDLEY AND MOORMAN, 13-18 JULY 1922Herbert O. Yardley Document Collection66472449/5/2019
 CORRESPONDENCE TO AND FROM YARDLEY, MOORMAN, MEETH, 27 FEBRUARY 1922Herbert O. Yardley Document Collection66470929/5/2019
 CORRESPONDENCE TO ASSISTANT CHIEF OF STAFF, G-2 FROM NUGENT, 22 NOVEMBER 1922Herbert O. Yardley Document Collection66473229/6/2019
 CORRESPONDENCE TO CHURCHILL FROM HEINTZELMAN, 13 NOVEMBER 1922Herbert O. Yardley Document Collection66473089/6/2019
 CORRESPONDENCE TO CHURCHILL FROM HEINTZELMAN, 31 OCTOBER 1922Herbert O. Yardley Document Collection66472909/6/2019
 CORRESPONDENCE TO CHURCHILL FROM MOORMAN, 18 NOVEMBER 1922Herbert O. Yardley Document Collection66473149/6/2019
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