Muslim Ibn Al-Hajjaj is the compiler of Sahih Muslim. He was born in Nishapur, Persia and also died in the city of his birth. He traveled through Iraq, Syria, Egypt and Arabian Peninsula to gather Hadith for his collection.
Sahih Muslim is highly regarded among Sunni Muslims and is considered the second most authentic collection out of the six major collections of Hadith after Sahih Bukhari.
This is the reason why the collection of Imam Muslim of Sahih Muslim is also regarded as a source of guidance.
The Compilation of Sahih Muslim:
Almost simultaneously with the Sahih Bukhari, another Sahih was being compiled. This was the Sahih of Imam Muslim. In this Sahih, he examined a third of a million Hadith of which he selected only about 12,000 which the expert scholars unanimously regard as sound.
Like Bukhari, Muslim regarded a Hadith as Sahih only when it had been handed down to him through a continuous chain of known and reliable authorities; was compatible with other sound Hadith and was free from defects.
The Sahih of Imam Muslim has been acclaimed as the most authentic collection of Hadith after that of Imam Bukhari which taken together are known as the Two Sahihs encompassing all topics of significance.
They are spoken as second only to the Holy Quran in term of authority.
However, more preference is given to Sahih Bukhari. It does not mean that the Hadith mentioned in Sahih Bukhari is more viable than Sahih Muslim.
It literally means that the overall content in Sahih Bukhari is more viable than of Sahih Muslim.
Collection of Hadith:
He selected four thousand Hadith out of three hundred thousand Hadith. This is because he mainly focused on compiling an authentic collection just like Sahih Bukhari.
He checked the complete Isnad (the chain of transmitters). He also focused on the criteria of the Hadith which shall not be against another Hadith which is already accepted as reliable.
This is what makes the Muslims consider it as the second most reliable source after Sahih Bukhari.
There is a total of 43 books with 7190 narrations mentioned in the collection of Sahih Muslim.
Why is Sahih Muslim not as Valid as Sahih Bukhari?
The reason is very simple as Imam Bukhari had an aim of collecting or compiling all the authentic Hadith whereas the aims of Muslim Ibn Al-Hajjaj were to compile those Hadith which were acceptable to Muslims on account of being more accurate.
There is a total of twenty two hundred traditions that are compiled in the collection of Imam Muslim out of which fourteen hundred traditions are those authentic traditions which are also mentioned in other reliable sources compiled.
Conclusion:
There is plenty of Hadith present in the collection of Imam Muslim. It can be consulted for the correct guidance of a person just like the collection of Imam Bukhari.
The reason why it can be consulted is that it is also referred as one of the Sahih.
