The arrival of the U-boat in the First War, and the addition of the bomber in the Second brought the Welsh coast and sea lanes into range of German attack. Wales had three important arteries around its coast: the Bristol Channel, St George's Channel, and the Irish Sea. These sea lanes, and the industrial ports surrounding them, were vital to the British war effort, and had to be protected at all costs. Airfields for airships, biplanes, seaplanes, fighters and bombers were established up and down the Welsh coast to combat the threat. Defending Wales tells the stories of the squadrons and flight crews responsible for safeguarding Welsh commerce and industry against a determined enemy in unreliable aircraft and often perilous weather conditions.