Captain Leonard T. Jones, USCG, was a pioneer in the development of clandestine radio intelligence for the U.S. Coast Guard in the 1930s and 1940s. His expertise in cryptology laid the foundation for the impressive successes Coast Guard cryptologists achieved against the Prohibition-era "Rumrunners" and against Germany during World War II. Captain Jones innovated the collection of Rumrunners' communications, which included shipborne collection, and getting the secure messages decrypted.
Trained by the Army's William Friedman, Captain Jones was a member of the team decrypting Japanese diplomatic codes in the early 1930s. During World War II, when the Coast Guard cryptanalytic unit was subordinated to the Navy's equivalent unit, he played a key role in maximizing the efforts of the two organizations, which had similar missions, but differed in organization and processes. Captain Jones led the successful effort to solve the Abwehr ENIGMA machine variant used by German agents in the Western Hemisphere. He also established and managed the cryptologic capabilities of the Office of Strategic Services, which resulted in the development of the first deployable field transmission and interception equipment used in support of U.S. clandestine operations.
Captain Jones' accomplishments prior to the war were important innovations in law enforcement, and during the war his leadership and achievements were major contributions to Allied cryptologic successes.