Kutub al-Sittah (Arabic: ٱلْكُتُب ٱلسِّتَّة, romanized: al-Kutub al-Sitta, lit. 'the Six Books'), also known as al-Sihah al-Sitta (Arabic: الصحاح الستة, romanized: al-Ṣiḥāḥ al-Sitta, lit. 'the Authentic Six') are the six canonical hadith collections of Sunni Islam. They were all compiled in the 9th and early 10th centuries, roughly from 840 to 912 CE and are thought to embody the Sunnah of Muhammad.
The books are the Sahih of al-Bukhari (d. 870), the Sahih of Muslim ibn al-Hajjaj (d. 875), the Sunan of Abu Dawud (d. 889), the Sunan of al-Tirmidhi (d. 892), the Sunan of al-Nasa'i (d. 915), and the Sunan of Ibn Majah (d. 887 or 889) as the sixth book, though some (particularly the Malikis and Ibn al-Athir) instead listed the Muwatta of Malik ibn Anas (d. 795) as the sixth book, and other scholars list Sunan of al-Daraqutni (d. 995) as the sixth book. Sunan ibn Majah largely won out as the sixth canonical book because its content has less overlap with the other five compared with its two contenders.
