Out of the six recognized authoritative Work of Hadith two of them are believed to be the Most authentic, namely the Sahih al-Bukhari and the Sahih Muslim.
Imam Muslim is Abu’l-Husain ‘Asakir-ud-Din Muslim b. Hajjaj al-Qushayri al-Naisaburi. “Muslim,” as hisnasba shows, belonged to the Qushayr tribe of the Arabs, an offshoot of the great clan of Rabi’a. He was born in Naisabur (Nishapur) in 202/817 or 206/821. He wrote many books and treatises on Hadith, but the most important of his works is the collection (Jami’) of his Sahih. Some of the commentators of Ahadith are of the opinion that in certain respects it is the best and most authentic work on the subject. Imam Muslim took great pains in collecting 300,000 Traditions, and then after a thorough examination of them retained only 4000, the genuineness of which is fully established his Methods of classification and annotation.
Muslim’s Sahih comes next to Sahih Bukhari. However, in certain respects Muslim is considered superior. Imam Muslim strictly observed many principles of the science of Hadith which had been slightly ignored by his great teacher Imam Bukhari (may Allah have mercy on both of them). Imam Muslim considered only such traditions to be genuine and authentic as had been transmitted to him by an unbroken chain of reliable authorities and were in perfect harmony with what had, (been related by other narrators whose trustworthiness was unanimously accepted and who were free from all defects. Moreover, Imam Bukhari, while describing the chain of narrators, sometimes mentions their kunya and sometimes gives their names. This is particularly true in case of the narrators of Syria. This creates a sort of confusion, which Imam Muslim has avoided. Imam Muslim takes particular care in according the exact words of the narrators and points out even the minutest difference in the wording of their reports.
Imam Muslim has also constantly kept in view the difference between the two well-known modes of narration, haddathana (he narrated to us) and akhbarana (he informed us). He is of the opinion that the first mode is used only when the teacher is narrating the hadith and the student is listening to it, while the second mode of expression implies that the student is reading the hadith before the teacher. This reflects his utmost care in the transmission of a hadith.
Imam Muslim has taken great pains in connecting the chain of narrators. He has recorded only that hadith which, at least, two reliable tabi’in (successors) had heard from two Companions and this principle is observed throughout the subsequent chain of narrators.