Hamza Yusuf is president of Zaytuna College. He has been a student of the classical Islamic tradition for over forty years, studying with some of the most respected scholars of our time, and serves as an adviser to the Center for Islamic Studies at the Graduate Theological Union in Berkeley. He is vice president of the Forum for Promoting Peace in Muslim Societies, an international initiative that seeks to address the root causes that can lead to radicalism and militancy. His most recent book is Purification of the Heart: Signs, Symptoms and Cures of the Spiritual Diseases of the Heart (2012).