This chapter describes what is known about the existence and the use of canon law books in Britain. The canon law always maintained a distinct identity. Many books dealt primarily with canonical problems or texts, and the canon law was in a real sense the dominant partner in the ius commune. Together with rules drawn from the Roman law, the canon law provided the principal source of the jurisprudence in the English ecclesiastical courts. Englishmen and Scotsmen were importers rather than producers of books relating to the canon law. The great canonists were Italian, French, German and Spanish. However, the Manipulus curatorum, written by the Spanish jurist Guido de Monte Rochen, was not simply imported. This book on duties of parochial clergy was printed in England seven times between 1498 and 1520. Of the imported texts, the comprehensive work on the Gregorian Decretals by Nicolaus de Tudeschis was particularly popular before the turn of the sixteenth century.