Sahih Muslim is a collection of
sayings and deeds of Prophet Muhammad (pbuh) (also known as the sunnah).
The reports of the Prophet's sayings and deeds are called ahadith.
Muslim lived a couple of centuries after the Prophet's death and worked extremely
hard to collect his ahadith. Each report in his collection was checked for
compatibility with the Qur'an, and the veracity of the chain of reporters
had to be painstakingly established. Muslim's collection is recognized by
the overwhelming majority of the Muslim world to be one of the most authentic
collections of the Sunnah of the Prophet (pbuh).
Muslim (full name Abul Husain
Muslim bin al-Hajjaj al-Nisapuri) was born in 202 A.H. and died in 261 A.H.
He travelled widely to gather his collection of ahadith, including to Iraq,
Saudi Arabia, Syria, and Egypt. Out of 300,000 ahadith which he evaluated,
only 4,000 approximately (including multiple hadith in a single one i.e. multiple
quotations) were extracted for inclusion into his collection based on stringent
acceptance criteria. Muslim was a student of Bukhari.
It is important to realize, however,
that Muslim's collection is not complete: there are other scholars who worked
as Muslim did and collected other authentic reports.