Sir Alexander Montagu George Cadogan (25 November 1884 – 9 July 1968) was a British diplomat and civil servant. He was Permanent Under-Secretary for Foreign Affairs from 1938 to 1946. His long tenure of the Permanent Secretary's office makes him one of the central figures of British policy before and during the Second World War. His diaries are a source of great value and give a sharp sense of the man and his life. Like most senior officials at the Foreign Office, he was bitterly critical of the appeasement policies of the 1930s but admitted that until British rearmament was better advanced, there were few other options. In particular, he stressed that without an American commitment to joint defence against Japan, Britain would be torn between the eastern and western spheres. Background and education Cadogan was brought up in a distinguished and wealthy aristocratic family as the seventh son and youngest child of George Cadogan, 5th Earl Cadogan, and his first wife Lady Beatrix Jane Craven, daughter of William Craven, 2nd Earl of Craven. He was the brother of Henry Cadogan, Viscount Chelsea, Gerald Cadogan, 6th Earl Cadogan, William Cadogan, and Sir Edward Cadogan. He was educated at Eton and Balliol College, Oxford, where he read History. Early Foreign Service career Cadogan had a distinguished career in the Diplomatic Service, serving from 1908 to 1950. His first posting was to Constantinople, where he "spent two happy years learning the craft of diplomacy and playing upon the head of Chancery a series of ingenious practical jokes." Cadogan's second posting was in Vienna, and during the First World War, he served in the Foreign Office in London. At the end of the First World War, he served at the Versailles Peace Conference. In 1923, he became the head of the League of Nations section of the Foreign Office and remained quite optimistic about the prospects for the League. He was less confident about the prospects of success for the Disarmament Conference in Geneva and became quite frustrated at the lack of trust necessary for joint disarmament. Performing this work, he developed an appreciation for his colleague and superior, Anthony Eden. Cadogan found him agreeable, and in a 1933 letter to his wife, he wrote, "He seems to me to have a very good idea of what is right and what is wrong, and if he thinks a thing is right he goes