Since its founding, the United States' declared principles of liberty and democracy have often clashed with aggressive policies of imperial expansion. In this sweeping narrative history, acclaimed scholar Walter Nugent explores this fundamental American contradiction by recounting the story of American land acquisition since 1782 and shows how this steady addition of territory instilled in the American people a habit of empire-building. From America's early expansions into Transappalachia and the Louisiana Purchase through later additions of Alaska and island protectorates in the Caribbean and Pacific, Nugent demonstrates that the history of American empire is a tale of shifting motives, as the early desire to annex land for a growing population gave way to securing strategic outposts for America's global economic and military interests. Thorough, enlightening, and well-sourced, this book explains the deep roots of American imperialism as no other has done.