This thesis deals with the 'Afar clan of KadIto (Asrat) and more specifically with the heritagernof Arabic MSS preserved in their Mosque of Dale, near the town of Aysa'Ita (Asaita) inrnAwsa. I explain how, when, why and by whom the library in the Mosque of Dale wasrnestablished, and describe its present chaotic condition. The heart of the thesis is a shortrncatalogue of 29 MSS which I found in that library, followed by a closer philological analysisrnof 10 of the MSS. In addition, the thesis discusses many issues relating to 'Afar culture,rngeography, history and economy. These include such general topics as 'Afar oral literature,rnfood, law, clothing, as well as a history of Islamic and Muslim leaders in 'Afar andrnparticularly in Awsa. The history and importance of the KadIto clan, and of other scholarlyrnclans such as the Kabirto and Seihak-SarTfa, are presented based on oral tradition