In this study, which originated as the author’s doctoral thesis in theology at Leiden, H. G. Kleyn deals with the life and works of Jacob Baradaeus, who stands as one of the most significant figures for miaphysite churches, and from whom the western Syriac church is often named. Kleyn studies Jacob’s life up to the time he became bishop and then looks at the role he played in the “monophysite” church to the time of his death in 578, including the tritheist controversy. The main part of the book concludes with an outline of Jacob’s writings. Four lengthy appendices conclude the work: 1. A list of the patriarchs of Constantinople, Alexandria, Antioch, and Jerusalem from 431 to the middle of the sixth century, 2. On the editor of the longer vita of Jacob, 3. The Arabic text of Jacob’s Confession, with a Dutch translation, and 4. A detailed list of Jacob’s letters contained in the British Museum (now British Library) ms. Add. 14602. Any reader that studies church history and theology in the east after the time of the Council of Chalcedon will find this volume important.