The early history of British aerial defence development is one of misdirection and delusion. The misdirection, judging by the criteria of successful aerial defence in World War II, was primarily in the downgrading of home defence measures including the fighter plane. The delusion, again judging by Britain’s efforts in that second world war, was primarily in the assumption of the effects to be obtained by strategic bombing. In both cases, the First World War was a major catalyst. Although events and writings before that war indicate the coming patterns, it was during that war that a great amount of the patterns are well established. Originally published in 1976, this work explores these origins and stresses the interaction between various diverse segments of English society in the formation of the major patterns. The working out of these patterns in the first half of the interwar years is also analysed, again with respect to diverse groupings in Britain.