Sahih Muslim or Al-Musnadu Al-Sahihu bi Naklil Adli is one of the Kutub al-Sittah (six major hadith collections) in Sunni Islam. It is highly acclaimed by Sunni Muslims as well as Zaidi Shia Muslims. and considered the second most authentic hadith collection after Sahih al-Bukhari. It was collected by Muslim ibn al-Hajjaj, also known as Imam Muslim. Its authenticity has sometimes been questioned due to the fact that it was written over 250 years after Prophet Muhammad SAW passed away. Regardless of this, Sunni Muslims believe it to be genuine and authentic. Sahih Muslim, together with Sahih al-Bukhari is termed as Sahihayn.