Photo-reconnaissance has come a long way from its faltering beginnings over the trenches of the Western Front during World War I, when unwieldy plate cameras were held over the cockpit sides of RFC BE2a biplanes. By the close of World War II, designated PR Spitfires could photograph Germany by day, while Mosquitoes could photograph by day or night with considerable success from heights of up to 36,000 feet. Following ten years of incredible advances in digital, optical and mechanical technology, the mid-1990s saw the RAF's Tornado GR1As using video-tape for PR, with a data link to relay pictures direct to interpreters on the ground, thus doing away altogether with wet film. This illustrated history was written at the request of the Association of Royal Air Force Photography Officers. Using official and personal records, the author traces the development of photo-reconnaissance from its earliest days. His narrative is supported by detailed illustrations.