The authors of the Six Books
Question

Who are the authors of the Six Books, and are there any da’eef (weak) ahaadeeth in their books?
Praise be to Allah.The authors of the Six Books are: 
1-Imam al-Bukhaari
2-Imam Muslim
3-Imam Abu Dawood
4-Imam al-Tirmidhi
5-Imam al-Nasaa’i
6-Imaam Ibn Maajah
There follow brief details about each of them. 
1 – Imam al-Bukhaari
His full name was Abu ‘Abd-Allaah Muhammad ibn Ismaa’eel ibn Ibraaheem ibn al-Mugheerah ibn Bardizbah al-Ja’fi al-Bukhaari. His grandfather al-Mugheerah was a freed slave of al-Yamaan al-Ja’fi, the governor of Bukhaarah, so he took his name after he became Muslim. Imam al-Bukhaari was born in Bukhaara in 194 AH. He grew up an orphan and started to memorize ahaadeeth before he was ten years old. When he was a young man he set out to travel to Makkah and perform the obligation of Hajj. He stayed in Makkah for a while, studying under the imams of fiqh, usool and hadeeth. Then he began to travel around, going from one Islamic region to another, for sixteen years in all. He visited many centers of knowledge where he collected ahaadeeth of the Prophet (peace and blessings of Allaah be upon him) until he had compiled more than 600,000 ahaadeeth. He referred to one thousand scholars of hadeeth and discussed these reports with them. These scholars were people who were known for their sincerity, piety and sound belief. From this huge number of ahaadeeth he compiled his book al-Saheeh, following the most precise scientific guidelines in his research as to their authenticity and in distinguishing the saheeh (sound) from the weak, and in finding out about the narrators, until he recorded in his book the most sound of the sound, although it does not contain all the saheeh ahaadeeth. The book’s full title is al-Jaami’ al-Saheeh al-Musnad min Hadeeth Rasool-Allaah (peace and blessings of Allaah be upon him) wa Sunanihi wa Ayaamihi. 
The governor of Bukhaara wanted al-Bukhaari to come to his house to teach his children and read ahaadeeth to them. But al-Bukhaari refused and wrote to him: “Knowledge is to be sought in its own house,” meaning that knowledge is to be sought not summoned. Whoever wanted to learn from the scholars should go to them in the mosque or in their houses. So the governor bore a grudge against him and ordered that he be expelled from Bukhaara. So he went to the village of Khartank which is near Samarqand, where he had relatives, and he settled there until he died in 256 AH at the age of 62. May Allaah have mercy upon him. 
2 – Imam Muslim
His full name was Muslim ibn al-Hajjaaj ibn Muslim al-Qushayri al-Nisapoori Abu’l-Husayn. He is one of the leading scholars of hadeeth and one of the most knowledgeable. He was born in Nisapoor on the day that Imam al-Shaafa’i died in 204 AH. He studied in Nisapoor, and when he grew up he traveled to Iraq and the Hijaaz to learn hadeeth. He heard ahaadeeth from many shaykhs, and many scholars of hadeeth narrated from him. The most famous of his books is his Saheeh which is known as Saheeh Muslim. This is one of the six reliable books of hadeeth. He spent nearly fifteen years compiling this book, which is second only to Saheeh al-Bukhaari in status and in the strength of its ahaadeeth. Many scholars have written commentaries on his Saheeh. 
His books also include Kitaab al-Tabaqaat, Kitaab al-Jaami’ and Kitaab al-Asma’, and others which exist in printed and manuscript form. He died in the city of Nasarabad, near Nisapoor, in 261 AH, at the age of 57. May Allaah have mercy on him. 
3 – Imam Abu Dawood
His full name was Sulaymaan ibn al-Ash’ath ibn Shaddaad ibn ‘Amr ibn Ishaaq ibn Basheer al-Azdi al-Sajistani, from Sajistan. Abu Dawood was the leading hadeeth scholar of his age. He is the author of al-Sunan, which is one of the six reliable books of hadeeth. He was born in 202 AH. He traveled to Baghdad where he met Imam Ahmad ibn Hanbal and stayed with him; he also looked like him.  He also traveled to the Hijaz, Iraq, Khurasaan, Syria, Egypt and the borders of the Islamic world. Al-Nasaa’i, al-Tirmidhi and others narrated hadeeth from him. He attained the highest degree of piety and righteousness. His book al-Sunan includes more than 5300 ahaadeeth. 
The caliph Abu Ahmad Talhah (al-Muwaffaq al-‘Abbaasi) asked three things of him: the first was that he should move to Basrah and settle there, so that seekers of knowledge could come to him, thus bringing more people to settle there. The second was that he should teach al-Sunan to his children. The third was that he should give exclusive classes to his children, for the children of the caliph should not sit with the common people. Abu Dawood said to him: As for the first, yes; as for the second, yes; as for the third, no way, because all people are equal when it comes to knowledge. So the sons of al-Muwaffaq al-‘Abbaasi used to attend his lessons, and they would sit with a screen between them and the people. He remained in Basrah until he died in 275 AH. May Allaah have mercy on him. 
4 – Imam al-Tirmidhi
His full name was Muhammad ibn ‘Eesa ibn Soorah ibn Moosa ibn al-Dahhaak al-Salami al-Tirmidhi, Abu Eesa. He came from Tirmidh, once of the cities of Transoxiana, after which he was named. He was one of the leading scholars of hadeeth and memorization of hadeeth. He was born in 209 AH and studied under al-Bukhaari; they had some of the same teachers. He began to seek ahaadeeth by travelling to Khurasaan, Iraq and the Hijaz. He became famous for his memorization of hadeeth, trustworthiness and knowledge.  His shaykhs included Ahmad ibn Hanbal and Abu Dawood al-Sajistani. He compiled al-Jaami’ which is counted as one of the six reliable books of hadeeth. In this book he examined the ahaadeeth in detail, which is of benefit to students of fiqh, because he mentions the ahaadeeth and most of his ahaadeeth deal with rulings of fiqh. He mentions the isnaads and lists the Sahaabah who narrated the hadeeth, so what he believes is saheeh he says is saheeh, and what he believes is da’eef he says is da’eef. He explains who among the fuqaha’ accepted the hadeeth and who did not. His Jaami’ is the most comprehensive of the books of al-Sunan, and is the most useful to the muhaddith (hadeeth scholar) and faqeeh. His other works include Kitaab al-Shamaa’il al-Nabawiyyah and al-‘Ilal fi’l-Hadeeth. He was blind for the latter part of his life, after he had travelled around and compiled saheeh reports from prominent and well-versed scholars. He died in 279 AH at the age of 70. May Allaah have mercy on him. 
5 – Imam al-Nasaa’i
His full name was Ahmad ibn Shu’ayb ibn ‘Ali ibn Sinaan ibn Bahr ibn Dinar al-Nasaa’i, Abu ‘Abd al-Rahmaan. He came from the city of Nasa in Khurasaan, after which he was named (Nasawi or Nasaa’i). He was born in 215 AH, and he was one of the leading scholars and muhaddiths of his time. His comments on al-jarh wa’l-ta’deel (the study of the soundness or otherwise of narrators of hadeeth) are highly esteemed by the scholars. Al-Haakim said: I heard Abu’l-Hasan al-Daaraqutni say more than once, “Abu ‘Abd al-Rahmaan is the foremost among all scholars of hadeeth, and he is the best evaluator of narrators of his time.” 
He was extremely pious and righteous, and he used to regularly observe the best kind of fasting (the fasting of Dawood), he used to fast on alternate days. He lived in Egypt, where his books became famous and people learned from him. Then he moved to Damascus, where he died on Monday 13 Safar 300 AH, at the age of 85. May Allaah have mercy on him. 
6 – Imam Ibn Maajah
His full name was Muhammad ibn Yazeed al-Rab’i al-Qazwayni, Abu ‘Abd-Allaah. His father Yazeed was known as Maajah, so he was known as Ibn Maajah. The name al-Rab’i refers to Rabee’ah, after whom he was named because his father was a freed slave of Rabee’ah . He was a famous hafiz and the author of the book of hadeeth called al-Sunan. He was born in Qazwayn, after which he was named, in 209 AH. He travelled to Iraq, Basrah, Kufa, Baghdad, Makkah, Syria, Egypt and al-Rai to write down hadeeth. He wrote three books during his travels: a book on Tafseer; a book on history, in which he compiled the reports of men who had written down reports of the Sunnah from the time of the Sahaabah until his own time; and his book al-Sunan. Ibn Maajah died on Monday 22 Ramadaan 273 AH, at the age of 64. May Allaah have mercy on him. 
Ruling on the ahaadeeth in these books:
With regard to Saheeh al-Bukhaari and Saheeh Muslim, the ummah accepts the ahaadeeth that are contained in these books, and they are agreed that everything in them is saheeh apart from a very few phrases which al-Bukhaari and Muslim narrated in order to explain why they are not sound, either explicitly or implicitly, as the scholars who wrote commentaries on these two books, such as Shaykh al-Islam Ibn Taymiyah (may Allaah have mercy on him), have explained. With regard to the other books of Sunan, they are not free of some da’eef (weak) ahaadeeth here and there. Some of them are noted as such by the authors themselves, and others have been pointed out by other scholars. They did not point out all the weak ahaadeeth, because they narrated the ahaadeeth with their isnaads, so it is easy for the scholars to tell the saheeh ahaadeeth from the da’eef by checking the chain of narrators and knowing who is reliable and who is weak.
 Among the famous scholars in this field were Ahmad, al-Daraqutni, Yahya ibn Ma’een, Ibn Hajar, al-Dhahabi, al-Waaqi and al-Sakhaawi. Among the contemporary scholars in this field are al-Albaani, Ahmad Shaakir and others. May Allaah have mercy on them all.
 And Allaah knows best.