Merriam Press Military Mograph 31. Fourth Edition (March 2012). Official history of the planning for the Normandy invasion. It was agreed at the Casablanca conference that the work of preparing for the grand assault on the fortress of Europe must go forward, and that it must be shared by the two nations which were eventually to cooperate in its execution. For the present it was decided to appoint a Chief of Staff to the Supreme Commander, under whom would be established a United States-British staff, with the duty of driving forward the plans for cross-Channel operations-a task which had hitherto been entrusted to a body kwn as the 'Combined Commanders.' It was expected that the Supreme Commander ultimately to be appointed would be a British general and that he would have an American deputy, so the mination of the Chief of Staff was decided on parallel lines. Lieutenant-General F. E. Morgan was appointed to this post, with Brigadier General R. W. Barker, of the U.S. Army (who had previously been associated with the Combined Commanders) as his deputy. To these men accordingly fell the task of building up the organization which was to plan the Allied invasion of North-West Europe. Taking the initial letters of his appointment-Chief of Staff to Supreme Allied Commander-General Morgan christened his organization COSSAC. 2 charts; Bibliography.