His research interests include African American history, gender history, history and memory, nationalism, and heroism. He is the author of The Spirit and the Shotgun: Armed Resistance and the Struggle for Civil Rights and co-editor of a number of volumes on the transnational dimensions of racism, racial violence, and nationalism, among them Racism in the Modern World: Historical Perspectives on Cultural Transfer and Adaptation and Crossing Boundaries: Ethnicity, Race, and National Belonging in a Transnational World.