Cryptologist, Security Specialist. William Friedman’s family fled Russia in 1892 to escape anti-Semitism, settling in Pittsburgh, Pennsylvania. He received a scholarship to work on genetics at Cornell University. Through this he met George Fabyan, who ran a private research laboratory. One project was regarding genetics; another was research into secret messages which Sir Francis Bacon had allegedly hidden in texts during the reigns of Elizabeth I and James I. He became director of Riverbank's Department of Codes and Ciphers as well as its Department of Genetics. He wrote a series of papers on cryptography, including the first description of the index of coincidence, an important mathematical tool in cryptanalysis. In World War I, the Department of Codes and Ciphers became the unofficial cryptographic center for the US Government. The government decided to set up its own code-breaking service and sent Army officers to train under him. He later enlisted in the Army and went to France to serve as the cryptographer for General John J. Pershing. In 1921 he became chief cryptanalyst for the War Department and later led the Signals Intelligence Service (SIS), a position he kept for many years. He wrote many studies on cryptography, one being Elements of cryptanalysis, which later was expanded to four volumes and became the U.S. Army's cryptographic main textbook. During the 1920s cipher machines were developed using typewriter mechanics and electrical circuitry. He realized that rotor machines would be important and analyzed their design, discovering several problems common to rotor-machine designs, then developed machines that were immune to his own attacks. The best was the SIGABA, which was the US's highest-security cipher machine in World War II. In 1939, the Japanese introduced a new cipher machine for their most sensitive diplomatic traffic, which SIS called PURPLE. An SIS team he determined that it used switches like those in automated telephone exchanges. SIS constructed an analog of the PURPLE machine, and this allowed SIS to decrypt Japanese traffic. One was the infamous December 7 message to the Japanese Embassy in Washington, D.C., ordering an end to negotiations with the US. In 1949 he became head of the cryptographic division of the Armed Forces Security Agency (AFSA) and in 1952 became chief cryptologist for the National Security Agency (NSA). He produced textbooks titled "Military Cryptanalysis", which were used to train NSA students. In 1955, he initiated, on behalf of the NSA, a secret agreement with Crypto AG, a Swiss manufacturer of encryption machines. The agreement resulted in many of the company's machines being compromised, so that the messages produced by them became crackable by the NSA. Friedman retired in 1956 and, with his wife, turned his attention to the problem that had originally brought them together: examining Bacon's supposed codes. Together they wrote a book entitled The Cryptologist Looks at Shakespeare, which won a prize from the Folger Library.