This volume documents the formation of the United States’ colonial and informal empire in the Pacific, Caribbean, and Central America at the turn of the twentieth century. Taking the cessation of hostilities with Spain as its starting point, this final volume traces the evolution of United States imperialism through to the end of the First World War. The expansion of the United States’ empire during the early twentieth century mirrored its rise on the world stage. Through overseas colonial expansion and the construction of an informal empire centred on the Panama Canal, the United States strove for hegemony in the Americas, and its imperial policies altered the lives of thousands who lived outside its national borders. Specific territories, such as Cuba, the Philippines, and Puerto Rico, are explored in this volume alongside regional and thematic accounts to provide a detailed and unique insight into the nature of United States imperialism. A host of historic perspectives are presented through a range of source material, including letters, government documents, and published material.