The Kutub al-Sittah (Arabic: الكتب السته;) are six books containing collections of hadiths (sayings or acts of the Prophet Muhammad), compiled by six Sunni Muslim scholars in the ninth century CE. They are sometimes referred to as Al-Sihah al-Sittah, which translates as "The Authentic Six". They were first formally grouped and defined by Ibn al-Qaisarani in the 11th century. Since then, they have enjoyed near-universal acceptance as part of the official canon of Sunni Islam.
Sunni Muslims view the six major hadith collections as their most important. They are, in order of authenticity:
The first two, commonly referred to as the Two Sahihs as an indication of their authenticity, contain approximately seven thousand ahadith altogether if repetitions are not counted, according to Ibn Hajar.
According to the Cambridge History of Iran: "After this period commences the age of the authors of the six canonical collections of Sunni hadith, all of whom were Persian. The authors of the six collections are as follows:
Muhammad b. Isma'il al-Bukhari, the author of the Sahih Bukhari, which he composed over a period of sixteen years. Traditional sources quote Bukhari as saying that he did not record any hadith before performing ablution and praying. Bukhari died near Samarqand in 256/869-70.