The U.S. Army's requirement for a lightweight general-purpose helicopter was formulated after the Korean War. The design of the Bell Model 204 won a competition in 1955 and was given the military designation H-40, which was later renamed HU-1 Iroquois. The initial design envisioned a helicopter that could be used for transport, air command and control on the battlefield, medical evacuation, fire coordination, and search and rescue.

Later, its missions expanded to include troop insertion/extraction, armed escort, and special operations. This title analyzes the entire technological background behind the development and use of the Huey 'Slick' in Vietnam, as well as covers all the major roles assigned to this transport aviation unit.