الكتب الأربعة
Shi'a Muslims seldom if ever use the six major hadith collections followed by the Sunni, as they do not trust many of the Sunni narrators and transmitters. They have their own extensive hadith literature. The best-known hadith collections are The Four Books, which were compiled by three authors who are known as the 'Three Muhammads'. The Four Books are: "Kitab al-Kafi" by Muhammad ibn Ya'qub al-Kulayni al-Razi (329 AH), "Man la yahduruhu al-Faqih" by Muhammad ibn Babuya and "Al-Tahdhib" and "Al-Istibsar" both by Shaykh Muhammad Tusi. Shi'a clerics also make use of extensive collections and commentaries by later authors.