"Since the end of the Vietnam War, historical research and writing on the Australian military involvement has only briefly dealt with intelligence aspects. Even less attention has been given to specialist intelligence collection, such as signals intelligence, imagery intelligence and human intelligence. This paper examines the modus operandi and effectiveness of specialist intelligence support to the 1st Australian Task Force in South Vietnam during the period from May 1966 to December 1971. It focuses on the activities of the little-known Detachment 1st Divisional Intelligence Unit and 547 Signal Troop. The paper examines how these units were organised and equipped, how they conducted their operations, and how effective they were in upporting combat units."--Publisher.