June marks the 160th Anniversary of the establishment of the Signal Corps, while 2020 marks the 75th anniversary of the end of World War II. Accordingly, this article will focus on the achievements and contributions of the Signal Corps during World War II.The scope of responsibilities held by the Signal Corps during World War II was significantly increased from its efforts in World War I. More than ever before, success in combat depended on good communications. Commanders using field radios could maintain continuous contact with their troops during rapid advances. At its peak strength in the fall of 1944, the Signal Corps comprised over 350,000 officers and men, more than six times as many as had served in the first World War.The Signal Corps had responsibility for one of the most important systems used during World War II – radar. Developed out of the Signal Corps Laboratories at Fort Monmouth, Army radar was first successfully demonstrated in 1937. Radar sets were in place in Pearl Harbor in December 1941 and detected the incoming Japanese bombardment, but unfortunately, the warnings were disregarded. Radar was credited with turning the tide of WWII, affecting the outcome of two key engagements: the Battle of Britain and the Battle of the Atlantic. The Japanese in the Pacific theater with at a distinct disadvantage as they were without radar, while the Allied ships were equipped with early warning radar.The Signal Corps Laboratories were responsible for designing and developing much of the communications equipment used by American forces in World War II. The laboratories developed the SCR-510 in 1941. This was the first FM backpack radio. This early pioneer in frequency modulation circuits provided front line troops with reliable, static-free communications. Multichannel FM radio relay sets (such as the AN/TRC-1) were fielded in the European Theater of Operations as early as 1943. FM radio relay and radar, both products of the labs at Fort Monmouth, are typically listed among the systems that made a difference in World War II.Other, more specialized fields were also under the purview of the Signal Corps. Photography had long been a part of the Signal Corps’ mission, but its value and versatility reached new levels, especially during the second half of the war, partially due to improvements in training and organization. The Photographic Division of the Office of the Chief Signal Officer became the Army Pictorial Service on June 17, 1942. Photographic training initially took place at Fort Monmouth, but was moved to the former Paramount Studios at Astoria, Long Island, in the new Signal Corps Photographic Center. The Signal Corps created orientation and training films, using the talents of notables such as Frank Capra, who was commissioned as a major in the Signal Corps in 1942, and Theodor Seuss Geisel, who served as a member of Capra’s documentary film crew. The Signal Corps also created an unprecedented pictorial record of World War II.Other WWII Signal missions included the homing pigeon program – pigeons proved particularly useful in places like the Pacific jungles where it was difficult to string wire. Many hero pigeons served valiantly during the battles, often receiving wounds but still delivering their messages. In addition to sending messages, the Signal Corps retained responsibility for the Army’s signal security and intelligence activity. The 2nd Signal Service Company performed intelligence-gathering duties. Activated at Fort Monmouth in 1939, the unit expanded to battalion size in April 1942. In the field, personnel operated the monitoring stations within the U.S and around the world. During the war, the battalion grew to a maximum of 5,000, including Women’s Army Corps members. In fact, the Signal Corps was the first agency of the Army Service Forces to request Women’s Army Corps personnel and utilized one of the highest percentages of female replacement communicators within the technical services.Throughout the war, the Signal Corps served a variety of functions to support the mission, and many of the most important missions grew out of the work of the dedicated civilians and soldiers at Fort Monmouth.