Abu Dawud Sulaymān ibn al-Ashʿath al-Azdi as-Sijistani (Persian/Arabic: أبو داود سليمان بن الأشعث الأزدي السجستاني), commonly known as Abu Dawud, was a noted Persian collector of prophetic hadith, and compiled the third of the six "canonical" hadith collections recognized by Sunni Muslims, the Sunan Abī Dāwūd. He was born in Sistan, in east of Iran, (then Persia) and died in 889 in Basra. Widely traveled among scholars of hadith, he went to Iraq, Egypt, Syria, Hijaz, Tihamah, Khurasan, Nishapur, and Marv among other places in order to collect hadith. He was primarily interested in jurisprudence, and as a result the collection by him focuses largely on legal hadith. Out of about 500,000 hadith, he chose 4,800 for inclusion in his work. He wrote some 21 books in total. Some of the most prominent are: Sunan Abī Dāwūd, containing some 4,800 hadith, is his principal work. They are usually numbered after the edition of Muhammad Muhyi al-Din `Abd al-Hamid (Cairo: Matba`at Mustafa Muhammad, 1354/1935), where 5,274 are distinguished. Some of his hadith are not sahih, but he claimed that all hadith listed were sahih unless specifically indicated otherwise; this has been controversial among Islamic scholars, since some, such as Ibn Hajar al-Asqalani believe some of the unmarked ones to be ḍaʿīf as well. In another work, Kitab al-Marāsīl, he lists 600 mursal hadith which, after extensive background investigation, he concludes are nonetheless sahih. Risālat Abī Dāwūd ilā Ahli Makkah; his letter to the inhabitants of Makkah describing his Sunan Abī Dāwūd.[2]