Patrick Boyde argues that the way in which Dante represents what he (or his fictional self) saw and felt was profoundly influenced by the thirteenth-century science of psychology. Professor Boyde offers an authoritative account of the way in which vision and the emotions were understood in Dante's lifetime. He rereads many of the most dramatic and moving episodes in the Comedy, and shows how knowledge of Dante's philosophical ideas can help us to understand the meaning of his journey toward the source of goodness and truth.