Sunan Abu Dawud is a collection of hadith compiled by the noble Imam Abu Dawud, Sulaiman bin Ash'ath bin Isaq bin Bashir bin Shaddad, Al-Azdi, As-Sijistani, who died in the year 275H. His collection is unanimously considered to be one of the six canonical collections of hadith (Kutub as-Sittah) of the Sunnah of the Prophet (ﷺ) and the first of the Four Books. It contains roughly 5274 hadith in 43 books.

Author bio:
He is Abu Dawud, Sulaiman bin Ash'ath bin Isaq bin Bashir bin Shaddad, Al-Azdi, As-Sijistani; he was born in the year 202 after Hijrah and he died in the year 275. As-Sijistani is derived from Sistan, a region which today stretches from south eastern Iran to south western Afghanistan.

The term As-Sijizi is also used as an ascription for Sistan, hence sometimes Abu Dawud was called: "Abu Dawud As-Sijzi"

He began to travel seeking Ahadith at a young age, and made his way to Baghdad by the time he was eighteen years old. His journeys, seeking knowledge, took him through the lands of Khurasan, Al-'Iraq, 'Arabia, Ash-Sham, and Egypt.

His most famous teachers include Ahmad bin Hanbal, Isaq bin Ibrahim, Yabya bin Win, Abu Bakr Ibn Abi Shaibah, his brother 'Uthman bin Abi Shaibah, 'All bin Al-Madini, and 'Abdullah bin Maslamah Al-Qan'abi, who was among those famous for reporting the Muw'atta' of Imam Malik.

His most famous students include his son, Abu Bakr 'Abdullah bin Abi Dawud, At-Tirmdhi, An-Nasa'i, Abu Bakr Al-Khalal, Ar-Ramahurmuzi, Ibn Abi Ad-Dunya', Ad-Duwlabi, as well as those who narrate the Sunan from him - a discussion of which follows.

Selected Statements About the Author and His Book
Al-Khattabi said: "The book of the Sunan, by Abu Dawud, is a noble book, there has not been another book written in the knowledge of the religion that is like it."

And he said: "I heard Ibn Al-'Arabl say - while we were listening to him (recite) this book; he pointed to the copy which was in front of him - 'If a man does not have any knowledge with him, except that of the Mushaf in which is Allah's Book, then this book, he would not have a need for any knowledge at all beyond the two of them."

Al-Khattabi said: "Abu 'Umar Muhammad bin 'Abdul-Wahid Az-Zahid - the companion of Abu A1-'Abbas Ahmad bin Yahya - informed me, he said: 'Ibrahlm Al-Harbi said: "When Abu Dawud wrote this book, Ahadith were made supple for him, just as iron was made supple for Dawud." Meaning the Prophet Dawud, peace be upon him

Al-Hafiz Adh-Dhahabl said: "Along with his Imdmat in Hadith and its fields, Abu Dawud was among the major Fuqaha', for his book proves that. He was among the distinguished companions of Imam Ahmad; he attended his lessons for a lengthy period of time, and he asked him about delicate issues, in both branches (Furu') and fundamentals (Usul), and he stayed upon the Madhhab of the Salaf, regarding following the Sunnah and submitting to it, and not delving into problematic Kalam."

His Books
Other than his Sunan, his letter to the people of Makkah, explaining the conditions he adhered to in compiling his Sunan, and his Masa'il of Imam Ahmad, Abu Däwud is known to have authored the following: At-Tafarrud, Al-Marasil, A 'lam An-Nubuwwah, Az-Zuhd, and An-Nasikh wal-Mansukh. Abu 'Ubaid Al-Ajurri compiled a book of questions that he asked Abu Dawud, entitled: Suw'alat Abi 'Ubaid A1-Ajjuri 'an Abi Dawud

His Objectives and Criteria
Regarding the level of narrators he included in his Sunan, Abu Dawud said: "There are no abandoned (Matruk) Hadith narrators in the book of As-Sunan which I wrote, and when there is a Munkar Hadith I clarified that it is Munkar, and there is nothing other than it which is similar for that topic." And the meaning of Munkar is an odd narration, whose narrators are disparaged.

And, he mentioned about the weak Ahadith in his book: "Whatever Hadith there is in my book that has a severe weakness, then I have clarified it, and whatever I did not mention anything about it, then it is Salih (good), and some of them are more correct than others."

It is clear from its context, that some of the Ahadith not clarified by him are weak, while he did not consider them to be severely weak.

And he said: "I wrote, from Allah's Messenger (ﷺ), five-hundred thousand Ahadith, selecting from them what I included in this book - meaning the book As-Sunan - so I collected four thousand Ahadith in it, mentioning what is Sahih, and what resembles that, and what is close to that."

Al-Hafiz Tim Mandah said: "Aim Dawud narrated weak chains of narration when he did not find anything else for the topic, because that is stronger to him then a man's opinion."