Abul Husayn Muslim ibn al-Hajjaj Qushayri al-Nisapuri (Arabic: أبو الحسين مسلم بن الحجاج القشيري النيشابوري) (lived c. 206-261 AH/c.821-875 CE), Muslim Author of the second most widely recognized collection of Hadith in Sunni Islam, "Sahih Muslim", "Muslim's authentic (collection)".
Among the author's teachers were included Harmala ibn Yahya, Sa'id ibn Mansur, Abd-Allah ibn Maslamah al-Qa'nabi, al-Dhuhali, al-Bukhari, Ibn Ma'in, Yahya ibn Yahya al-Nishaburi al-Tamimi, and others. Among his students were al-Tirmidhi, Ibn Abi Hatim al-Razi, and Ibn Khuzaymah, each of which wrote works on hadith too. After many studies throughout Arabia, Egypt, Iraq and Syria, he settled down in his hometown of Nishapur where he first met Bukhari, with whom he would have a friendship until his death.
He died in 875 CE in Nishapur, where he was also buried.
Estimates on how many hadiths are in his books vary widely from 12,000 to 3,033 depending on whether they remove the duplicates, and consider only the text or the isnad as well. The book is said to share about 1900 hadiths with Bukhari's Sahih.