Herbert Yardley Herbert Osborne Yardley ( April 13 , 1889 – August 7 , 1958 ) was an American cryptologist best known for his book " The American Black Chamber " ( 1931 ) . The title of the book refers to the Cipher Bureau , the cryptographic organization of which Yardley was the founder and head . Under Yardley , the cryptanalyst s of The American 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 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 let go due to pressure from Washington . Early life . Yardley was born in 1889 in Worthington , Indiana . He learned to use the telegraph from his father , Robert Kirkbride Yardley , a station master and telegrapher for a railroad . His mother , Mary Emma Osborn Yardley , died when he was 13 . After graduating high school in 1907 , Yardley went to the University of Chicago , but dropped out after one year and went back to Worthington , where he worked as a telegrapher for a railroad . He spent his free time learning how to play poker and applied his winnings towards his further schooling . In 1912 , after passing the civil service exam , he was hired as a government telegrapher . Yardley began his career as a code clerk in the U . S . State Department . He accepted a Signal Corps Reserve commission and served as a cryptologic officer with the American Expeditionary Forces in France during World War I . Codebreaking . His career in cryptology began with his work in the code room , as he broke the U . S . government codes that crossed his desk . At that time , American codes were very weak and Yardley solved them easily . He was shocked to learn that President Wilson was using a code that had been in use for over ten years . The weakness of American codes worried Yardley , especially considering the war in Europe , so in May 1916 he began writing a hundred - page “ Solution of American Diplomatic Codes ” , which he gave to his boss . Breaking American codes got Yardley wondering about the codes of other countries . American participation in the war gave Yardley an opportunity to convince Major Ralph Van Deman of the need to set up a section to break other countries ' codes . In June 1917 , Yardley became a 2nd lieutenant in the Signal Corps and head of the newly created eighth section of military intelligence , MI - 8 . One early case was the cryptogram discovered in the clothing of German spy Lothar Witzke after he was arrested at the Mexican border in 1918 . The evidence linked Witzke to significant sabotage activity in the U . S . Yardley proved to be a very good administrator and during the war the people of MI - 8 performed well even if they did not have any spectacular successes . After the war , the American Army and the State department decided to jointly fund MI - 8 and Yardley continued as head of the " Cipher Bureau " . They located their operations in New York City for legal reasons . Cracking Japanese codes was a priority . David Kahn states : After almost a year , Yardley and his staff finally managed to break the Japanese codes and were still reading Japanese diplomatic traffic when Washington hosted the Washington Naval Conference in 1921 . The information the Cipher Bureau provided the American delegation regarding the Japanese government ' s absolute minimum acceptable battleship requirements was instrumental in getting the Japanese side to agree to a 5 : 3 ratio instead of the 10 : 7 ratio the Japanese Navy really wanted . This allowed Japan only 18 battleships to 30 for the U . S . and 30 for Great Britain instead of the 21 battleships Japan desired . This was the height of Yardley ' s cryptanalytic career . Unfortunately , Yardley spent much of his time in New York involved in unrelated activities . Also , the flow of diplomatic telegrams dried up as companies became less willing to break the law to help the government . In Washington , William Friedman was actively exploring cryptographic frontiers for the Army . The Cipher Bureau was becoming irrelevant . However , it was moral indignation that finally doomed the bureau . When Henry L . Stimson , Secretary of State under President Herbert Hoover , found out about Yardley and the Cipher Bureau , he was furious and withdrew funding , summing up his argument with " Gentlemen do not read each other ' s mail " . Some believe that Stimson was most offended when Yardley bragged that he could read all traffic of the Vatican , for it was after this remark Stimson turned and left the room . " The American Black Chamber " . MI - 8 closed its doors for good on October 31 , 1929 , just two days after the stock market crashed . With Yardley ' s esoteric skills in very low demand , he took up writing about his experiences in codebreaking to support his family . His memoirs , " The American Black Chamber " , were published by Bobbs - Merrill in 1931 . The book outlined the history of the first U . S . Signals Intelligence ( SIGINT ) organization , described the activities of MI - 8 during World War I and the American Black Chamber in the 1920s , and illustrated the basic principles of signals security . This work was instantly popular . Its critics at the time concluded that it was " the most sensational contribution to the secret history of the war , as well as the immediate post - war period , which has yet been written by an American . Its deliberate indiscretions exceed any to be found in the recent memoirs of European secret agents . " In the U . S . , 17 , 931 copies were sold , with 5 , 480 more sold in the U . K . It was translated into French , Swedish , Japanese , and Chinese . The Japanese version sold an unprecedented 33 , 119 copies . This book was an embarrassment to the U . S . government and compromised some of the sources Yardley and his associates used . Through this work an estimated 19 nations were alerted that their codes were broken . Much of the post - World War I codebreaking was done by obtaining copies of enciphered telegrams sent over Western Union by foreign diplomats , as was the custom before countries had technology for specialized communications devices . William F . Friedman , considered the father of modern American signals intelligence ( SIGINT ) gathering , was incensed by the book and the publicity it generated in part because sources and methods were compromised and because Yardley ' s contribution was overstated . While Yardley may have thought that publishing this book would force the government to re - establish a SIGINT program , it had the opposite effect . The U . S . Government considered prosecuting him , but he had not technically violated existing law regarding protection of government records . In 1933 , the Espionage Act was amended , PL 37 ( USC Title 18 , section 952 ) , to prohibit the disclosure of foreign code or anything sent in code . Yardley ' s second book , " Japanese Diplomatic Codes : 1921 - 1922 " , was presented to the dynasty of royalty in full printed form and a part of the manuscript scribbled on , and also burnt and seized by U . S . marshals and never published . The manuscript was declassified in 1979 . " The American Black Chamber " represents an early example of the exposé national security books that would appear after World War II , such as " The Codebreakers " and " The Puzzle Palace " , which also focus on U . S . SIGINT operations and organizations . In 1935 , Metro - Goldwyn - Mayer released " Rendezvous , " a fictional film " based on a book by Herbert O . Yardley . " The film , starring William Powell and Rosalind Russell , and directed by William K . Howard , concerns a German spy ring stealing U . S . government codes during World War I , as well as U . S . Army efforts to crack German codes . After the Black Chamber . Yardley did cryptologic work for Canada ( although pressure from the U . S . on the Canadian government meant this was limited ) and China during World War II , but he was never again given a position of trust in the U . S . government . Despite this , in 1999 he was given a place in the National Security Agency Hall of Honor . None of Yardley ' s many later attempts at writing were as successful as " The American Black Chamber " , though he published several articles and three spy / mystery novels ( " The Blonde Countess " , " Red Sun of Nippon " , and " Crows Are Black Everywhere " ) . He contributed as a writer and technical advisor to several movies , including " Rendezvous " , based very loosely on one of his novels , " The Blonde Countess " . His 1957 book on poker , " Education of a Poker Player " , which combined poker stories with the math behind the poker strategies , sold well . Another book of cryptographic memoirs , " The Chinese Black Chamber " , about his work in China , was declassified and published in 1983 . Yardley died on August 7 , 1958 , nearly a week after having a major stroke . He is buried at Arlington National Cemetery , Grave 429 - 1 of Section 30 . Yardley is a member of the Military Intelligence Hall of Fame . The National Cryptologic Museum ' s library has 16 boxes of Yardley ' s personal files .