Abstract: This book examines the views on friendship of the great medieval philosopher Thomas Aquinas. For Aquinas, friendship is the ideal type of relationship that rational beings should cultivate. The book argues that Aquinas fundamentally revised some of the main features of Aristotle's paradigmatic account of friendship so as to accommodate the case of friendship between radically unequal beings: man and God. As a result, Aquinas presented a broader view of friendship than Aristotle's, allowing for a higher extent of disagreement, lack of mutual understanding, and inequality between friends.

Keywords: Thomas Aquinas, relationship, Aristotle, man and God, disagreement, mutual understanding, inequality