Muslim ibn al-Hajjaj
Aside from the Qur'an the "hadith" or tradition of what Muhammed is supposed to have said and done are important literature. The entire body of these acts and words are called "sunnah" or way and the ones regarded as "sahih" or genuine of them are collected into hadith. Some of the most significant collections of hadith include those by Muslim ibn al-Hajjaj and Muhammad ibn Isma'il al-Bukhari.