Her research examines the ways in which “race” operated as a potent signifier of difference—cultural, biological, social, and political—in the United States and the West during the “long 19th century” and the early 20th century. She is the author of In Search of Brightest Africa: Reimagining the Dark Continent in American Culture, 1884-1936 (2010), and is currently working on a monograph and digital history project that explores U.S. engagement with the “African Question” from 1847-1919.