The Psalms has been Dietrich Bonhoeffer's most beloved book of the Bible. Not only in his letters but also spiritual writings and sermons, texts from the Psalms are cited frequently. In order to resist the Nazis' anti-Judaism, which brings about the abandonment of the Old Testament, Bonhoeffer claims that ”the Old Testament is the book of the Church” and ”the book concerning Christ.” As a result, Bonhoeffer published a booklet titled Psalms: The Prayer Book of the Bible in 1940. In this book, Bonhoeffer argues, the Psalms is the prayer of Christ; Christ prays these psalms through David. Therefore, the Psalms doubtlessly should be the best prayers for Christians. Psalms: The Prayer Book of the Bible is the last publication in Bonhoeffer's life. Insofar as the content is concerned the booklet is by no means less important than Creation and Fall, unfortunately, it dose not attract the attention that it deserves from theological scholarship. It is, therefore, the main purpose of this essay to highlight the historical and theological singularity of Psalms: The Prayer Book of the Bible. In so doing the essay firstly retrospects to the social context of its publication and its particular place in Bonhoeffer's thoughts. Secondly, it argues that the method Bonhoeffer uses to interpret the Psalms is the so-called Christocentric hermeneutics, since Creation and Fall. Lastly, it points out, the Psalter for Bonhoeffer is not only significant in thought but also in his spiritual life.