This book unravels the ethnic history of California since the late nineteenth-century Anglo-American conquest and institutionalization of "white supremacy" in the state. Almaguer comparatively assesses the struggles for control of resources, status, and political legitimacy between the European American and the Native American, Mexican, African-American, Chinese, and Japanese populations. Drawing from an array of primary and secondary sources, he weaves a detailed, disturbing portrait of ethnic, racial, and class relationships during this tumultuous time. The U.S. annexation of California in 1848 and the simultaneous discovery of gold sparked rapid and diverse waves of immigration westward, displacing the already established pastoral Mexican society. Almaguer shows how the confrontation between white immigrants and the Mexican ranchero and working class populations was also a contestation over racial status in which racialization influenced and was in turn influenced by class position in the changing economic order. Partly because of the Treaty of Guadalupe Hidalgo, which granted U.S. citizenship and other rights, parts of the Mexican population were integrated into the emerging Anglo society more easily than other racialized groups. A case study of Ventura County highlights declining political and economic fortunes of the Mexican elite while showing how Mexican, Japanese, Chinese, and Indian populations were permanently relegated to the bottom of the class structure as unskilled manual workers. The fate of the Native American population provides perhaps the most extreme example of white supremacy during the period. Popular conceptions of Native Americans as "uncivilized and "heathen," justified the killing of more than 8,000 men, women, and children between 1848 and 1870. Many survivors were incorporated at the periphery of Anglo society, often as indentured laborers and virtual slaves. Underpinning the institutional structuring of white supremacy were notions such as "manifest destiny," the inherent good of the capitalist wage-system, and the superiority of Christianity and Euro-American culture, all of which helped to marginalize non white groups in California and justify Anglo-American class dominance. As other racialized groups assumed new roles, Almaguer assesses the complex interplay between economic forces and racial attitudes that simultaneously structured and allocated "group position" in the new social hierarchy. California remains a contested racial frontier, as political struggles over the rights and opportunities of different groups continue to reverberate along racial lines. Racial Fault Lines is an invaluable contribution to our understanding of ethnicity and class in America, and the social construction of "race" in the Far West.