The theme of this first of four volumes of the official British history of the Second World War devoted to the RAF's strategic bomber offensive against Germany is in its sub-title 'Preparation'. Beginning with the lessons learned from air bombing in its infancy during the Great War, the authors divide their book into three parts: strategy; operations; appreciations and results. No aspect of Britain's role in the war, as the authors acknowledge in their preface, has been and remains more controversial than the air war against German cities. These books, the product of ten years' research, are an essential repository of facts, based on official documents - then still secret - in the archives of the Cabinet Office, the Air Ministry and Bomber Command. Other papers on which this account is based include the official despatches of the Chief of Bomber Command, Sir Arthur Harris, the writings and interrogations of Germany's armaments minister, Albert Speer, and papers from the Air Historical Branch. In addition to written sources, the authors consulted many of the air chiefs, scientists and other officials who directed and led the offensive. - including those of the USAF.From an initial reluctance to bomb German forests because they were private property, Britain's bombing offensive, one of the few weapons available to it in the dark early days of the war, escalated after the battles of France and Britain and the opening of the Luftwaffe's Blitz on Britain, from precision targets to mass area bombing of cities. This book takes the story up to the opening of 1943 with the first thousand bomber raids, the creation of the Pathfinder Force, and the beginning of daylight bombing. The narrative is accompanied by diagrams, six maps and 20 photos of the leading figures behind the offensive, the aircraft involved, and 'before and after' pictures of the raids and their results. This calm, dispassionate book is essential reading for all who are interested in a subject which remains burningly relevant in the 21st century.