What does it mean to be a Muslim philosopher, or to philosophize in Islam? In Open to Reason, Souleymane Bachir Diagne traces Muslims’ intellectual and spiritual history of examining and questioning beliefs and arguments to show how Islamic philosophy has always engaged critically with texts and ideas both inside and outside its tradition. Through a rich reading of classical and modern Muslim philosophers, Diagne explains the long history of philosophy in the Islamic world and its relevance to crucial issues of our own time.