From the earliest centuries of the church, believers have seen the beatitudes (Matthew 5:3-10) as central to their identity as Christians. Given the traditional importance of the beatitudes it is rather surprising to discover so little examination of the history of their interpretation. This book seeks to address an aspect of that neglected history. Its principal work is a close analysis of how Augustine, John Calvin, and Karl Barth dealt with the beatitudes -- how they interpreted the beatitudes in sermons and commentaries and how they used those interpretations in some of their better known works. Contrary to what some scholars have assumed, each of those three theologians interprets the beatitudes to describe not only one’s interior life, but also how Christians are called to practice their faith in the world. In an appendix the book includes an English translation of Calvin’s sermon on the beatitudes.