This is a study of the intellectual history of the Andalusi Christians (alias Mozarabs) of Spain based on their Arabic and Latin polemical writings against Islam, c. 1050-1200. The first part of the book examines how these authors drew on earlier Oriental Arab-Christian theology, twelfth-century Latin-Christian theology, and the foundational texts of Islam itself - the Quran and Hadit - for polemical purposes. The second part is a critical edition and English translation of the most important source, the Liber denudationis siue ostensionis aut patefaciens (alias Contrarietas alfolica). Since it describes how the Andalusi Christians participated in the pluralistic milieu in which they lived, this study will be of interest to historians of medieval Spain's minority groups, Christian-Muslim relations, and the Arab-Christian tradition.