With the advent of the aeroplane, twentieth century warfare moved into a third dimension. First used in action by Italy during the Libyan War of 1911–12, aeroplanes played an important part in the First World War and a major – and still controversial – role in the Second World War. The manned bomber, central to all theories of strategic air power, remained unchallenged as the most powerful means of delivering ordnance from the air until the advent of the intercontinental ballistic missile in 1957. Thereafter airpower has had strenuously to justify its place as a co-equal in the defence triad both in budgetary and in operational terms. To do this, airmen have deployed history to justify their claims to parity with – or even pre-eminence over – the other services. They have also sought to demonstrate that late twentieth century wars have been won by strategic air power – or could have been so won had the air arm been properly and freely used. The eight essays collected together here range widely among these themes, casting fresh light on some of the continuing controversies and offering insights into new areas of airpower history.