After numerous collections of Hadith had been made during the third century of Islam six works became recognised as authoritative. Two of them are believed to be completely authentic, namely the Sahih al-Bukharii and the Sahih Muslim. The other four, Sahih al-Tirmidhi, Sunan Ibn Majah, Sunan Abu Dawud and Sunan Nasa'i are also highly esteemed but are regarded lower in category to Sahih Bukhari and Muslim
'Maa wara-un-nehr, in Central Asia has given the world many religious scholars whose names are inscribed for ever on the pages of Islamic history. Among them we find such a distinguished person as Abu Abdur Rahman Ahmad bin Shu'aib an Nasai'i. His book Sunan occupies an outstanding place among six principal Hadith collections (Sihah Sittah) known in the Muslim world. Imam Nasa'i was very careful while selecting materials for his work. This is why many scholars consider that the book Sunan Nasa'i occupies third place in Hadith collections after Sahih al-Bukhari and Sahih Muslim. It contains 5764 tradition, said to have been carefully collected out of 500,000.'