Count Nikolaus Ludwig von Zinzendorf was without question the most influential German theologian between Luther and Schleiermacher. He was the force behind modern Protestant missions, launched efforts that eventually became the ecumenical movement, and influenced some of the most significant theological projects of the modern world from Schleiermacher’s to Barth’s and Bonhoeffer’s. He was convinced that in important respects the Christian church of his day had lost its way both intellectually and practically. In these speeches, given to overflow crowds in Berlin, he brought to expression what he held to be the absolute and nonnegotiable center of Christian existence-the main thing. Here he laid out for public view the heart of all his activity, the guiding reality of his life. In these speeches Zinzendorf focuses on fundamental theological themes. One senses the influence upon him of the Pietist movement and of Orthodox theology. One gains an appreciation for his bold idiosyncrasy, his willingness to stand apart, and to bear witness. But above all, one gains here an insight into the very heart of Zinzendorf.