The birth and flowering of canonical jurisprudence in the twelfth century is one of the most striking and fruitful developments of the age, marking an important turn in the history of the Church and in framing the essential elements of the rule of law in political and social life. Raymond of Penyafort was an important participant in these developments. Born near Barcelona in 1175, he became a teacher of canon law at Bologna, the greatest centre of legal studies. He joined the newly founded Order of Preachers (Dominicans), and championed multilingual education of the friars for a more effective evangelization of Muslims and Jews. He became Master General of the Order in 1238, and died in 1275. He was canonized in 1601 and has been declared the patron saint of canon lawyers. Pope Gregory IX appointed Raymond to produce a comprehensive compilation of papal legal decisions. The result, the Decretals of Gregory IX (1234), would remain normative in the Catholic Church until 1917. Raymond drew on it to compose his Summa on Marriage, a summary of learned reflection on the law of marriage, to aid his Dominican brothers in hearing confessions, where numerous problems touching on marriage would have been encountered. The definition of marriage and of its ends, stages and impediments, arrangements and consequences are the subject of the work. This translation of it offers students and scholars alike a comprehensive presentation of the medieval teaching on marriage - learned in content, practical in orientation. Languages : English, Latin.