This study examines the development and usefulness of US air attack theory and doctrine during the interwar period, 1919-1941. This period represents more than 20 years of development in US Air Corps attack theory and doctrine. It was the first peacetime period of such development. Attack aviation during this time was a branch of aviation used to provide direct and indirect combat support to ground forces in the form of machine-gun strafing, light bombing, and chemical attacks.