by Imam Muslim, translation by Abdul Hamid Siddiqui
Sahih Muslim (Arabic: ???? ????, ?a?i? Muslim, full title Al-Musnadu Al-Sahihu bi Naklil Adli) is one of the Six major collections of the hadith in Sunni Islam, oral traditions relating to the words and deeds of the Islamic Prophet Muhammad. It is the second most authentic hadith collection according to Sunni Muslims, the most authentic book of hadith after Sahih Al-Bukhari. It was collected by Muslim ibn al-Hajjaj, also known as Imam Muslim. Sahih translates as authentic or correct.
Imam Muslim (Muslim ibn al-Hajjaj) was born in 202 AH in Naysabur, Iran into a Persian family (817/818CE) and died in 261AH (874/875CE) also in Nishapur. He traveled widely to gather his collection of ahadith (plural of hadith), including to Iraq, the Arabian Peninsula, Syria and Egypt. Out of 300,000 hadith which he evaluated, approximately 4,000 were extracted for inclusion into his collection based on stringent acceptance criteria. Each report in his collection was checked and the veracity of the chain of reporters was painstakingly established. Sunni Muslims consider it the second most authentic hadith collection, after Sahih Bukhari. However, it is important to realize that Imam Muslim never claimed to collect all authentic traditions as his goal was to collect only traditions that all Muslims should agree on about accuracy.
According to Munthiri, there are a total of 2200 hadiths (without repetition) in Sahih Muslim. According to Muhammad Amin,  there are 1400 authentic hadiths that are reported in other books, mainly the Six major Hadith collections.