Author: Sheikh al-Tayefah, known as Sheikh Toosi [Abu Ja'far, Muhammad son of Hasan Toosi], one of the most distinguished Shiite Ulema/Jurisprudents of the fifth century Hegira (385-460 A.H)
Subject: This book is a collection of those Narrations/Hadiths of the Ahl-ul-Bayt [the Infallible Household of the Holy Prophet of Islam (s.a.)] that are seemingly "at variance with each other" or "show discrepancies" in their contents. By compilation of this book, Sheikh Toosi has successfully tried to prove the authenticity of the correct Narrations or Hadiths among the undocumented ones.
In this book, Sheikh Toosi collected any Narration/Hadith, a "contrary Narration" of which, too, had been on hand.
All of the Narrations/Hadiths quoted in this book revolve around the subject of Fiqh (Islamic Jurisprudence and Religious Decrees).
This book has been considered to be one of the most authentic and credible collections of Shiite Narrations/Hadiths, to which every Islamic Jurisprudent, Scholar, and exegete of the Holy Koran has to refer as an obligatory requirement.
It is among the four most important Shiite reference books called "Kutub Arba'ah" [i.e. The Four Books]. The other three are: Sheikh Toosi's other outstanding book entitled "Tahzib al-Ahkam", Sheikh Kuleini's "Al-Kafi", and Sheikh Sadooq's "Man la Yahzarahul-Faqih".
Sheikh Toosi's Al-Istibsar was written subsequent to the request of Ulema [Islamic Scholars] and readers of his other famous book entitled "Tahzib al-Ahkam". They had asked the Sheikh to compile a book including all seemingly contradictory Narrations/Hadiths, conduct a research on them to investigate their authenticity, and finally distinguish correct Narrations from the incorrect ones.
"A group of Shiite Ulema (Scholars) studied my extensive book entitled "Tahzib al-Ahkam" and noted that it contained the largest part of Narrations and Hadiths on the lawful (Halal) and unlawful (Haram) acts as well as religious laws, precepts, and decrees on Fiqh [Islamic Jurisprudence]. They further noticed that there is no Narration or Hadith on Shiite fundamentals and precepts overlooked or missing in this book except a few rare ones. They opined that "Tahzib al-Ahkam" deserved to become a great treasure for the seekers after the science of Fiqh, especially for the Ulema to recollect their past learning, and for other less learned scholars to gain expertise in inference of religious decrees. They went on to suggest that I write another book after gathering together "the contrary Narrations/Hadiths" for examining and determining their credibility..."
In this book, Sheikh Toosi places Narrations/Hadiths considered by him as authentic and correct in the beginning. Then they are followed by his mention of the contrary narrations; and indeed, he has tried his best not to omit any of them. Then he proceeds to examine the contrary narrations, which constitutes the special feature of the book.
1- This book is unique among others of its kind, being the first one to write about the contrary Narrations/Hadiths and evaluate their authenticity.
2- Comprehensiveness of Al-Istibsar is so impressive that Ibne Tavoos commented that if there was any contrary Narration on a particular topic, a mention of it could be surely found in Al-Istibsar.
3- Sheikh Toosi, as stated earlier, quotes first the authentic and acceptable Narrations/Hadiths and then deals with the other ones.
Al-Istibsar does not include all chapters of Fiqh, but only those narrations that are subject to some contrary ones. However, it follows the same usual sequence of the chapters as in the Fiqh books, i.e. with the topics beginning from Taharat (cleanliness) and ending with Diyat (blood money).
The book is divided into three parts. The first and the second deal with Ibadat [ritual acts, e.g. daily prayers, fasting, etc.] The third chapter addresses other subjects of Fiqh such as contracts, transactions, Islamic laws for financial or social affairs, up to the matters of "penal laws" and "blood money".
The Narrations in the book total 5511 Hadiths, which is the number fixed by Sheikh Toosi himself to prevent any later manipulation of others.
Due to the significance and value of this book, its name has constantly been among the list of the important books; and Islamic scholars frequently issued "authorizations" for their pupils to narrate Hadiths from this outstanding book. Texts of many of such Authorizations are presently available at the end of some copies of Al-Istibsar.
In compiling this book, Sheikh Toosi has taken advantages from two famous libraries, both located at that time in the city of Baghdad. Both libraries were complete with copious numbers of the best authentic books and original manuscripts. Many of the copies were transcribed by the disciples of the Infallible Imams (a.s.).
The first library he used belonged to his distinguished teacher, Sayyed Mortaza, and contained 80,000 books.
The other one was the bigger library called Shapoor library, established for the Shiite Ulema in the locality of Karkh, Baghdad.
Unfortunately, the Shapoor Library was set on fire during brutal attack of some of the enemies of the Ahl-ul Bayt (A.S.), and the Islamic world lost a great treasure of books. Some of the manuscripts exclusively belonged to the Shapoor Library.
Sheikh Toosi spent nearly forty years of his lifetime in conducting research and extracting or writing down Narrations/Hadiths, especially of the Holy Imams (A.S.) from the books and manuscripts in the aforementioned libraries, and gifted his collections to the posterity. This adds to the ever-increasing worth of his extremely valuable writings.
Agha Bozorg Tehrani, in his valuable book entitled "Al-Dhari'ah Ila Tasanif al-Shi'a", comments on Al-Istibsar as follows: "The book Al-Istibsar is one of the Four Reference Books of Narrations/Hadiths which has served as the means for inference of Islamic decrees and laws by Shiite Jurisprudents/Scholars from the time of its completion up until now."
Ibne Edris, in his book [Sara'er], states: "This book was written by Sheikh Toosi for incorporating and discussing the Narrations/Hadiths which seem to be at variance. In this book, contrary narrations were brought together by the writer who then produced a consensus of opinions gleaned from them."
As mentioned earlier herein, Ibne Tavoos, too, in his book Fat-hul Abwab underlines that "any contrary narration existing on a given topic is most likely to be found in Al-Istibsar. No doubt, it is most useful to a researcher".
Many Shiite Ulema have written explanations for Al-Istibsar, including the following:
1) Sheikh Abdul-Latif, son of Ahmad son of Abi Jam'e Harethi Shami Ameli (a pupil of Sheikh Baha'ei) in his book entitled "Jame'ul-Akhbar Fi Eizah-il-Istibsar";
2) Shahide Awwal, Muhammad Ibne Makki, in his book Nukatul-Irshad;
3) Sayyid Mirza Hasan son of Abdul-Rasool Husseini Zonoozi Khu'ei (1172-1223 A.H.) in his work Sharhe Istibsar;
4) Amir Muhammad son of Amir Abdul-Wassi' Khatoon Abadi (d.1116 A.H.), a son-in-law of Allameh Majlesi, in his book Sharhe Istibsar;
5) Sheikh Abdul-Reza Tufaili Najafi in Sharhe Istibsar;
6) Ibne Alwandi, Faqihe Kazemi, Qasim son of Muhammad Jawad (d. some time later than 1100 A.H.), a contemporary of Sheikh Horr Ameli, in his work Sharhe Istibsar; and
7) Allamah Sayyid Muhsin son of Hasan A'arji Kazemi (d.1127 A.H.), in his book Sharhe Istibsar.
Many marginal notes, too, were written by eminent Ulema, including the following:
1) Sheikh Hasan son of Zaynuddin [the author of Ma'alim],
2) Mowla Muhammad Amin son of Muhammad Sharif Astar Abadi (d. 1033 A.H),
3) Mir Muhammad Baqir son of Shamsuddin Muhammad Husseini, popularly known as Damad, who passed away in 1041 A.H.
4) Fazilah Hamidah, daughter of Mowla Muhammad Sharif Rooydashti (d. 1087 A.H.),
5) Mowla Abdul-Rashid son of Mowla Nooruddin Shooshtari (d. approx. 1078 A.H.),
6) Sayyid Mirza Muhammad son of Ali son of Ibrahim Astar Abadi, the famous biographer (d. 1028 A.H),
7) Sayyid Muhammad son of Ali son of Hussein Moosawi Ameli, [the author of Madarek, (d.1009 A.H.), and
8) Sayyid Ne'matullah Jazayeri, son of Abdullah Moosawi Shooshtari (d.1112 A.H.)
Narrations and Hadiths in the first and the second part of Al-Istibsar are fully documented. But in the third part, only the names of the authors of the books from which Sheikh Toosi has quoted are mentioned. At the end of the book, however, he has given his own authentication of the named narrators by mentioning the full chain of the intermediate ones. Thus, all quoted Narrations and Hadiths turn into well-documented texts.
(1) Mowla Sharif Ali son of Hasan [his commentary is entitled "Mashikhatul-Istibsar"]
(2) Hasan son of Ali son of Ibrahim Alawi [His commentary on Mashikhah is titled as Asanidul-Istibsar';
(3) Sheikh Fakhruddin son of Muhammad-Ali son of Ahmad son of Turaih Najafi (d.1085 A.H.) who wrote a book on Mashikhah entitled Awatiful-Istibsar'
(1) An old MS in the beautiful Naskh' script, written in the year 1090 A.H.: this copy is recited for and confirmed by the Late Allameh Majlesi, and his signature is available at the end of the copy. It is now preserved in the Amir al-Mu'menin (A.S.) Library;
(2) A MS beautifully written and illuminated by golden lines in 1078 A.H., which is kept in the library of Sayyid Muhammad Baghdadi, with marginal writings of Muhaqqiq Sayyid Muhammad Ameli, the author of Madarikul Ahkam'; and
(3) A nice MS decorated in gold for a personage in India, written in the year 1072 A.H. by one, named Ali Reza.