The Hadith, the recorded traditions and sayings of Muhammad, are a major source of moral guidance and religious law to Muslims, and is second only to the authority of the Quran for Muslims.
The six canonical collections of Hadiths in orthodox Islam are known as al-kutub al-sittah (“the six books”). These six collections are:
• Sahih Al-Bukhari (compiled by Muslim scholar Abū ʿAbd Allāh Muḥammad ibn Ismāʿīl al-Bukhārī, who lived AD 810-870).
• Sahih Muslim (compiled by Muslim scholar Abū Al-ḥusayn Muslim Ibn Al-ḥajjāj Al-qushayrī, who lived AD 817-875).
• Sunan An-Nasā'ī (compiled by Abūʿ Abd al-Raḥmān al-Nasāʾī, who lived AD 830-915).
• Sunan Abu Dawud (compiled by Muslim scholar Abū Dāʾūd al-Sijistānī, who lived AD 817-889).
• Jami Al-Tirmidhi (compiled by Muslim Scholar Abū ʿĪsā Muḥammad ibn ʿĪsā ibn Sawrah ibn Shaddād al-Tirmidhī, who died in AD 892).
• Sunan Ibn Majah (compiled by Muslim Scholar Abū ʿAbdallāh ibn Mājā, who lived AD 824-886).
(The best-authenticated Hadiths, the Sahihs, are by Al-Bukhari and Muslim Ibn Al-ḥajjāj. These two Hadiths are the second most important source of Islamic law and practice after the Quran itself).
There are also other Hadiths, such as:
Muwatta Malik (compiled by Muslim theologian Mālik Ibn Anas, who lived AD 715-795. This is the oldest surviving compendium of Islamic law. Sometimes Sunnis consider this one a part of the al-kutub al-sittah).
Musnad Ahmad (compiled by Muslim theologian Aḥmad Ibn Ḥanbal, who lived AD 780-855. Aḥmad Ibn Ḥanbal was the formulator of the Ḥanbalī, the most strictly traditionalist of the four orthodox Islāmic schools of law).
Al-Adab al-Mufrad al-Bukhari (compiled by the same Muslim scholar, Abū ʿAbd Allāh Muḥammad ibn Ismāʿīl al-Bukhārī, who also compiled the most reliable and authentic Hadith in Islamic history, Sahih Al-Bukhari. He lived AD 810-870).