Sunan Abu Dawud is one of the Kutub Al-Sittah (Six major hadiths books), collected by Abu Dawud. Abu Dawud collected 500,000 hadith, but included only 4,800 in this collection. Muslims regard this collection as fourth in strength of their Six major Hadith collections. It took him 20 years for collecting the ahadis. He made series of journeys to meet most of the foremost traditionists of his time and acquired from them the most reliable ahadis quoting sources through which it reached him. Since the author collected ahadis which no one ever assembled together, his sunan has been accepted as standard work by scholars from many parts of the Islamic world, especially after Ibn Al-Qaisarani's inclusion of it in the formal canonization of the six major collections.