During 1991 the Royal Australian Air Force will celebrate its seventieth anniversary. To commemorate this milestone, the Chief of the Air Staff commissioned a history of the service, covering the formative years from its establishment in 1921 until 1939, thereby filling the gap between the official histories of Australian air power in the First and Second World Wars. The outcome of this initiative is "The third brother", a major historical achievement which is destined to become the definitive study of the period. This comprehensive account of the RAAF in the years leading up to the start of the Second World War documents the establishment and growth of the service, its personalities and problems, its low points as well as the triumphs. In particular it describes the struggle of the third member of Australia's defence triad to gain acceptance as a co-equal of the Army and Navy. Anyone who has ever served in the RAAF , or has an interest in the story of the development of Australian defence capability, will be sure to find new facts and insights concerning the last-born of Australia's "great military family". "Chris Coulthard-Clark, one of Australia's best-known writers of military history, is the author of "Action Stations Coral Sea; No Australian need apply; Gables, ghosts and Governors-General" and "Duntroon. This book is intended for students and researchers in military history.