Born in India into a family of soldiers and diplomats, Slessor made the first aerial attack on a Zeppelin and went on to serve in the Middle East over the Western Front in World War I; and postwar on the North-West Frontier in India. Rated an exceptional staff officer, in the inter-war years, under the influence of Sir Hugh Trenchard, he became a devout proponent of strategic bombing and a strong advocate of the importance of air support for ground forces. Through his writing and teaching he gained a reputation as a deep thinker, and as Director of Plans in the Air Ministry from 1937, was closely concerned with rearmament. When the conflict came, he became a major cog in the policy machine. Serving variously as Head of 5 Group Bomber Command (1941), with Portal throughout 1942 and at Casablanca in 1943, his high point came as Head of Coastal Command in 1943 with the defeat of the U-Boats, and his nadir in August 1944 with the tragedy of the Warsaw uprising. Post-WWII he continued to influence thinking whether in office or retirement, being an ardent opponent of the Soviet Union. Indeed his Global Strategy Paper in 1952 was arguably the basis of all strategic thinking until the end of the Cold War. Immensely self-confident, Slessor expressed himself forcefully and was dismissive of such luminaries as Alexander, Tedder, Dulles, Nasser, Ibn Saud and Anthony Eden. Vincent Orange was given full access to Slessor's diaries, letters and papers; and to all relevant official documentation. His assessment of his subject's contribution to history is cogent, persuasive and above all, well balanced and honest. This is the first full biography of an exceptional man about whom the eminent historian Sir Michael Howard wrote 'A truly great man. His contribution to the winning of the war has been outstanding. No less was his contribution to subsequent keeping of the peace'.