This book takes a comprehensive look at the undercover war, revealing just how much of WWII was won away from the battlefields. From the British cryptologists to the European resistance fighters, this book uncovers the stories of extraordinary people and their chance finds, lucky accidents, dogged determination and moments of sheer brilliance, to expose how the war was really won. It includes an intriguing glimpse at the early history of the computer - its spectacular uses and subsequent development and features vivid first-hand accounts from the staff of Bletchley Park, the French and Dutch resistance fighters, the American secret agents and the British SOE saboteurs. It is illustrated with secret maps, resistance maps and rare archive photographs.