Jamharat Rasa’il al-‘Arab fi ‘Usur al-‘Arabiyah al-Zahirah (4 vol) جمهرة رسائل العرب في عصور العربية الزاهرة

This work of Ahmad Zaki Safwat, great for literary studies and history – it’s a work in which all the letters from the time of the Prophet until the end of the Abbasid period.