When Canadian troops and British Commandos made their now famous 'reconnaissance in force' against the harbour town of Dieppe on 19th August 1942, they were supported and protected by the largest array of Royal Air Force aircraft ever seen in WW-II until that time. Air Marshal, Trafford Leigh-Mallory, AOC of Fighter Command's Number 11 Group, was given command of the air operation and had 46 Spitfire, 8 Hurricane, 3 Typhoon and 4 Mustang Squadrons under his direction, as well as 7 Boston and Blenheim squadrons of 2 Group and Fighter Command. On 19th August Leigh-Mallory commanded more squadrons than were available to Air Chief Marshal Hugh Dowding at any one time during the Battle of Britain two years previously. This book provides a detailed, minute by minute, hour by hour, blow by blow account of operations on a day which has become accepted as the one on which the Royal Air Force fought its greatest air battle. The RAF flew nearly 3,000 sorties: the Luftwaffe 945, Air combat, ground attacks, bombing and smoke laying missions cost the RAF over 100 aircraft and the Luftwaffe nearly 50. All this happened in just 16 hours. In addition to the in-depth research into the RAF's activities on this August day 68 years ago, there are also many personal accounts from pilots who took part adding color to the story of this unique battle in the history of the Royal Air Force.