In 1940 Great Britain was in dire straits and facing Nazi invasion. Twenty-four destroyers had been lost during the Dunkirk evacuation. Winston Churchill asked the United States' President Roosevolt for 'the loan of forty or fifty of your oldest destroyers'. He got them - eventually. In response to Churchill's request, and in return for the use by the US of British bases in the Caribbean, fifty mothballed 'flush-deck' destroyers of the United States Navy were supplied to the Royal Navy. This book presents a comprehensive history of their service, to their operational use and a detailed assesment of their service and achievements.