As we approach the 100th anniversary of the outbreak of the First World War, students of history will revisit the causes, conduct and aftermath of the war. In each of these, Sir Eyre Crowe played a very significant role. Yet, outside academic and diplomatic circles, his name is little known. An outsider in the Foreign Office, he neither attended an English public school nor university. He was born and educated in Germany. Yet he rose because of his unique expertise to be the Permanent Under-Secretary from 1920 until his death in 1925, during which time he worked, not always amicably, with...