"Dietrich Bonhoeffer here gives one of his secrets behind the powerful witness of his own life. He had learned to pray the Psalms and from them drew on the power of God in his years of imprisonment. In this introduction, Bonhoeffer discusses the various types of Psalms and how they can be used to enrich our prayer life. In a brief biographical sketch, Eberhard Bethge, friend and biographer of the author, helps us understand the man who used the Psalms as his prayer book." --Covenant Theological Seminary Bookstore