The Douglas A-26 was the fastest bomber in the USAAF inventory, and went on to serve the US and Allied nations for many years. It was conceived as a replacement for the company's A-20 "Havoc/Boston", as well as the North American B-25 "Mitchell" and Martin B-26 "Marauder" medium bombers.
Development began in 1940, led by the prolific Edward Heinemann, with the XA-26A prototype taking to the air on July 10, 1942. In June 1942, the contract was amended to include a second prototype, the XA-26B, with forward-firing guns installed in a solid nose. Extensive testing resulted in a standard arrangement of six .50 caliber machine guns. Weapons capacity was rated at 6,000 pounds of internal and external stores - a full ton more than the Marauder.
Invaders first saw combat on June 23, 1944, with the Fifth Air Force in the Pacific. They also served in the European theater, starting in September 1944. A total of 1,355 B-models were produced at Douglas plants in Long Beach, CA and Tulsa, OK.