I am a historian of the United States with an emphasis on the nineteenth-century United States, African American history, women, gender and sexuality, and empire. Trained in U.S. and Japanese institutions, I have always taken comparative and transnational approaches in my study of history. In all of my work, I explore how race and its related processes—class, gender, and sexuality—organized and were organized by global structures and circumstances as well as by systems of exclusion and inclusion at national, colonial, and imperial levels.