hadith (hädēth') [key], a tradition or the collection of the traditions of Muhammad, the Prophet of Islam, including his sayings and deeds, and his tacit approval of what was said or done in his presence. The term, which literally refers to an individual tradition, is also used as a synonym of sunna, the normative custom of the Prophet and his companions, and as the name of a scholarly discipline. Hadith, as a discipline, consists of two branches, the first concerned with the validation of the individual traditions through the process of biographic examination of its chain of transmitters back to the Prophet (isnad), and the second concentrating on the actual content of the validated traditions (matn) as a source of religious authority. Since the formalization of Islam, this source of authority has been viewed as second only to the Qur'an. Hadith currently exists in two main sets of collections, corresponding to the Sunni and Shiite division within Islam. Sunni Islam recognizes as authoritative the collections of Bukhari and Muslim followed in importance by those of Abu Dawud, Tirmidhi, an-Nasai, and Ibn Maja. Shiite Islam accepts only traditions traced through Ali's family. The major Shiite collections are those of al-Kulini, al-Babuya al-Qummi, and al-Tusi.
See W. A. Graham, Divine Word and Prophetic Word in Early Islam (1977); G. H. A. Juynboll, Muslim Tradition (1981).