His research focuses on mystical Islam in West Africa and Senegal as well s the new African diaspora. Publication include Fighting the Greater Jihad: Amadu Bamba and the Founding of the Muridiyya of Senegal, 1853-1913 (Ohio University Press, 2007) as well as articles in African Affairs, Journal of African History, International Journal of African Historical Studies, Journal of Religion in Africa, Africa Today and other scholarly journals in the United States and in France.