To many Americans in the nineteenth and twentieth centuries, the West was simultaneously the greatest symbol of American opportunity, the greatest story of its history, and the imagined blank slate on which the country's future would be written. From the Spanish-American War in 1898 to the Great Depression's end, from the Mississippi to the Pacific, policymakers at various levels and large-scale corporate investors, along with those living in the West and its borderlands, struggled over who would define modernity, who would participate in the modern American West, and who would be excluded. In Making a Modern U.S. West Sarah Deutsch surveys the history of the U.S. West from 1898 to 1940. Centering what is often relegated to the margins in histories of the region--the flows of people, capital, and ideas across borders--Deutsch attends to the region's role in constructing U.S. racial formations and argues that the West as a region was as important as the South in constructing the United States as a "white man's country." While this racial formation was linked to claims of modernity and progress by powerful players, Deutsch shows that visions of what constituted modernity were deeply contested by others. This expansive volume presents the most thorough examination to date of the American West from the late 1890s to the eve of World War II.