Abbas was a celebrated man of letters and a prolific writer during his lifetime. He republished Ibn Bassam's 12th-century biographical dictionary of the Arabian Peninsula's intellectuals, editing it into eight "mammoth" volumes.[12] Abbas' analysis of Abd al-Wahhab Al-Bayati's poetry and the significance of Bayati's references to Sisyphus and Prometheus was criticized as Shmuel Moreh; Abbas saw the references as being philosophical allegory, while Moreh tied them to the fall of the Iraqi Communist Party.[13] Abbas contributed significantly to the history of Arabic literature and writers, and was responsible for collecting and compiling the work of Abd al-Hamid al-Katib in 1988,[14] uncovering archived letters between the Umayyad secretary and the empire's last caliph which shed light on the inner workings of the dynasty in its last days.[15] He was also one of the few writers to critically analyze the Kharijites, a now extinct sect of Islam.[16] Though reserved in revealing his own beliefs, Abbas adhered to Sunni Islam and leaned toward the Zahiri school of Islamic jurisprudence. He was responsible for reviving the works of Ibn Hazm, one of the main philosophers of the school and of Islam in general, editing and republishing many of them and even uncovering previously unpublished works on Ibn Hazm's legal theory from various archives; Abbas' 1983 edition of Ibn Hazm's book on legal theory Ihkam is considered a key moment in Arab intellectual history and the modernist revival of Zahirite legal method.[17]