This thesis is concerned with the Arabic versions of the Gospels. It is an attempt to examine a substantial number of Arabic manuscripts which contain the continuous text of the canonical Gospels copied between the eighth and the nineteenth centuries and found in twenty-one different library collections in Europe and the Orient. Following the introduction, Chapter Two presents the state of research from the middle of the nineteenth century to the present time. Chapter Three introduces and reflects on the two hundred plus manuscripts examined in this work. Chapters Four to Eight concentrate on grouping these manuscripts into twenty-four families and examining their Vorlagen (Greek, Syriac, Coptic and Latin). In order to examine the relationship between the families, phylogenetic software is used. Consequently, the manuscripts are grouped into seven different mega clusters or tribes. Finally the date of the first translation of the Gospels into Arabic is addressed and (a) provisional date(s) suggested based on the textual and linguistic analyses of the manuscripts. The conclusion in Chapter Ten gives the overall contribution made by this thesis and also future avenues for the study of the Arabic versions of the Gospels.