Marshal of the British Royal Air Force (RAF) and noted military theorist. Born in Rahniket, India, on 3 June 1897, John Slessor joined the Royal Flying Corps in 1915 during World War I and saw action in the defense of London and in France, Egypt, and Sudan. Between the wars he served in a range of posts, including instructor, duty, and staff positions in the Air Ministry. He spoke and wrote about airpower extensively, authoring a book titled Air Power and Armies in 1936. He was a key RAF planner just before and during the early years of World War II. He was assigned to a series of senior command positions in Bomber Command, Coastal Command, and the Mediterranean and Middle East forces, with promotions to air commodore in September 1939, air vice marshal in January 1941, and air marshal in February 1943. He was the lead planner for the postwar RAF force structure, earning promotion to air chief marshal in 1946.

Slessor served as chief of the Air Staff from January 1950 to January 1953, when he retired from active duty. He was promoted to marshal of the RAF in June 1950. He ardently advocated a nuclear-armed, long-range bomber force. After retirement in 1953, he became a commentator on strategic issues and published two books on defense policy, Strategy for the West and The Great Deterrent, as well as an autobiography. He advocated a force structure that included adequate conventional forces but relied on thermonuclear weapons for strategic deterrence against the Soviet Union and tactical nuclear weapons for enhanced firepower in smaller conflicts and theater operations. His concepts were similar to the New Look defense posture of President Dwight D. Eisenhower. Slessor died in Wroughton, England, on 12 July 1979.

Jerome V. Martin

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Further Reading
Slessor, Sir John Cotesworth. Central Blue: The Autobiography of Sir John Slessor, Marshal of the RAF. New York: Praeger, 1957.; Slessor, Sir John Cotesworth. Strategy for the West. New York: William Morrow, 1954.; Slessor, Sir John Cotesworth. The Great Deterrent. New York: Praeger, 1957.