Army Service Forces in the context of "European Theater of Operations"

Brehon Burke Somervell (9 May 1892 – 13 February 1955) was a general in the United States Army and Commanding General of the Army Service Forces in World War II. As such he was responsible for the U.S. Army's logistics. Following his death, The Washington Post lauded him as "one of the ablest officers the United States Army has produced".

Somervell graduated near the top of his United States Military Academy class of 1914 and was commissioned in the United States Army Corps of Engineers. During World War I he served with the Pancho Villa Expedition in Mexico and the American Expeditionary Force in France in logistical posts. He was also decorated for gallantry in the Meuse-Argonne Offensive.

The United States Army Air Forces (USAAF or AAF) was the major land-based aerial warfare service component of the United States Army and de facto aerial warfare service branch of the United States during and immediately after World War II (1941–1947). It was created on 20 June 1941 as successor to the previous United States Army Air Corps and is the direct predecessor of the United States Air Force, today one of the six armed forces of the United States. The AAF was a component of the United States Army, which on 2 March 1942 was divided functionally by executive order into three autonomous forces: the Army Ground Forces, the United States Army Services of Supply (which in 1943 became the Army Service Forces), and the Army Air Forces. Each of these forces had a commanding general who reported directly to the Army chief of staff.

The AAF administered all parts of military aviation formerly distributed among the Air Corps, General Headquarters Air Force, and the ground forces' corps area commanders and thus became the first air organization of the U.S. Army to control its own installations and support personnel. The peak size of the AAF during World War II was over 2.4 million men and women in service and nearly 80,000 aircraft by 1944, and 783 domestic bases in December 1943. By "V-E Day", the Army Air Forces had 1.25 million men stationed overseas and operated from more than 1,600 airfields worldwide.

The Army Ground Forces were one of the three autonomous components of the Army of the United States during World War II, the others being the Army Air Forces and Army Service Forces. Throughout their existence, Army Ground Forces were the largest training organization ever established in the United States. Its strength of 780,000 troops on 1 May 1942 grew to a peak of 2,200,000 by 1 July 1943. Thereafter its strength declined as units departed for overseas theaters.

The Services of Supply or "SOS" branch of the Army of the USA was created on 28 February 1942 by Executive Order Number 9082 "Reorganizing the Army and the War Department" and War Department Circular No. 59, dated 2 March 1942. Services of Supply became one of the three autonomous components of the Army of the United States on 9 March 1942. It was renamed the Army Service Forces on 12 March 1943, as it was felt that the term "supply" did not accurately describe its broad range of activities. From the day of inception (and even before) in 1942 through the end of WWII, the SOS/ASF was commanded by Lieutenant General (later General) Brehon B. Somervell.

Most theaters of war had their own logistical organization, usually also named the Services of Supply. The European Theater, and its SOS was subdivided into the ETO and the MTO (Mediterranean Theater of Operations) for the Operation Torch invasion of North Africa, then Sicily, then Italy, though the MTO was largely supplied by the SOS out of Great Britain. The SOS-ETO became TSF/ET (Theater Service Forces—European Theater) on D-Day, 6 June 1944, the term SOS was abolished, and its activities on the continent were referred to as COM-Z, or Communications Zone.

Wilhelm Delp Styer (22 July 1893 – 26 February 1975) was a lieutenant general in the United States Army during World War II. A graduate of the United States Military Academy at West Point with the class of 1916, he was commissioned into the United States Army Corps of Engineers and served with the Pancho Villa Expedition and on the Western Front. Between the wars he obtained a degree in civil engineering from the Massachusetts Institute of Technology. He was executive officer and assistant district engineer of the New York Engineer District.

During World War II, Styer was deputy commander of the Construction Division in the Quartermaster Corps and later the Corps of Engineers. In March 1942, he became the chief of staff of the Services of Supply. He became deputy commanding general of the Army Service Forces in August 1943, as the Services of Supply was renamed. In this capacity he served on the Military Policy Committee, which oversaw the Manhattan Project.