This book derives from a lifelong interest in the Second World War bequeathed to me by my mother, who long ago handed me a book about Winston Churchill. The British people fought against terrible odds in 1940-1941. How did they succeed? I endeavor here to answer that question by examining British management of what was arguably their most vital resource in the Second World War: merchant shipping. In exploring the causes and consequences of British dependence upon the United States for the merchant ships necessary to wage that war, I have incurred many debts.

I would like to thank the staffs of several resource libraries and archival centers I visited for their cooperation and guidance. They aided my visits to the Imperial War Museum in Lambeth, the National Maritime Museum in Greenwich, the Public Record Office in Kew, the Churchill College Archives at Cambridge University, the Franklin D. Roosevelt Library in Hyde Park, New York, the Library of Congress and the National Archives in Washington. I owe a special debt to Alma Topen at the University of Glasgow who provided access to the James Lithgow Papers. The Manuscripts and Archives Department at Yale's Sterling Memorial Library was unfailingly helpful. Yale's Seeley Mudd Library and the Yale Computer Center provided a friendly working environment.

Professor Paul Kennedy's sponsorship, advice, guidance, and example have been of inestimable value. His patient labor through this manuscript pointed the way to its conclusion.