This thesis consists of a critical edition of Tuhfat dhawi al-irab fi mushkil al-asma' wa al-nisab by Abu al-Thana' Nur al-Din Mahm-ud b. Ahmad b. Muhammad known as Ibn Khatib al-Dahshah: an alphabetical dictionary which deals with the vocalization of the names and nisbas which occur in the three canonical hadith collections, namely the Sahihayn and the Muwatta' regardless of whether these names occur in the isnads or in the matn of these books. This work is divided into two parts, an introduction and the edition of the text. The first part consists of a biographical account of the author, his works and a review of the previously published edition of the Tuhfah. A study of the work comprising the author's sources, a discussion of his alleged carelessness in copying, his arrangement, the subject and the title of the work is undertaken. A description of the MSS and an account of the method of edition adopted is also given. The second part comprises a critical edition of the Tuhfah, depending on five MSS, with the necessary explanatory notes, indices and bibliography.