Josef Albo (around 1380-1444) is considered to be the last Jewish philosopher of the Middle Ages. Following the basic ideas of Maimonides he wrote his Sefer ha-iqqarim , his Book of Principles , in the interval between the Tortosa Disputation and the expulsion of the Jews from Spain with the intention to strengthen his correligionists against Christian attacks. In early modern times his work became an important source for Christian Hebraists in theological discussions. This is a detailed monograph on Josef Albo. It analyzes the Christian reception of the Sefer ha-iqqarim , and, due to its interdisciplinary approaches, should be suitable for scholars of philosophy and Jewish studies as well as theology and history.