The most authoritative collections of Shi`ite hadiths
The most famous and authoritative collections of Shi'ite hadiths are four works which, in terms of their importance for Shi'ism, correspond to the Six Correct Collections in Sunni Islam. These are al-Kafi fi 'ilm al-din (The Sufficient in the Knowledge of Religion) by Thiqat al-Islam Muhammad ibn Ya'qub al-Kulayni (d. 329/940), Man la yahduruhu al-faqih (For him not in the Presence of Jurisprudent) of Shaykh al-Saduq Muhammad ibn Babuyah al-Qummi (d. 381/991), Tahdhib al-ahkam (Rectification of the Statutes) by Shaykh al-Ta'ifah Muhammad al-Tusi (d. 460/ 1068) and al-Istibsar fi ma ukhtulif fihi min al-akhbar (Reflection upon the Disputed Traditions) also by al-Tusi.
'Al-Kafi' by Al-Kulayni
The author of al-Kafi was thiqat al-Islam, Abu Ja'far Muhammad b. Ya'qub b. Ishaq al-Kulaini al-Razi. He died in 328 A.H. or 329 A.H. (939 or 940 A.D.). Very little is known of his life and there is some dispute as to whether the nisba by which he is known is al-Kulaini or al-Kulini. However, it is agreed that it refers to a village in Iran, Kulain or Kulin; both were villages there. 
He first worked as a religious scholar and faqih (student of fiqh or religious law) among the Imami-Shi'i scholars of al-Raiy in Iran. Then he moved to Baghdad and became head of the religious and legal scholars of the Imamis during the time when al-Muqtadir was Caliph. Al-Kulaini's life's work took place during the time of the sufara' of the Mahdi (the agents who acted on behalf of the Hidden Imam during the lesser occultation, al ghaiba al-sughra). 
Al-Kulaini is accredited with several works during this period. Among these are, as well as al-Kafi, a Kitab al-rijal, (a book in which men are assessed as authorities for traditions), al-Radd 'ala 'l-Qaramata ("Refutation of the Carmatians", Rasa' il al-a'immata "Letters of the Imams" and an anthology of poetry about the Imams. Only al-Kafi appears to have survived. 
Al-Kafiis a collection of the traditions taught by the Prophet and the Imams and handed down to the Muslim Community by the disciples of the Imams. The name al-Kafi means "that which is sufficient" that is, the book was intended to be a comprehensive collection of Imami-Shi'i traditions. This is explained by al-Kulaini in his introduction to the work:
"...You wanted to have a book which would be sufficient (for your religious needs) (kafin), which would include all kinds of knowledge ('ilm) of religion, which would be adequate for the student, and to which the teacher might refer. Thus it could be used by anyone who wanted knowledge of religion and of legal practice ('amal) according to sound traditions (athar) from the truthful ones (the Imams) ..."
It is claimed that it took al-Kulaini twenty years to complete al-Kafi. It is indeed a very full and comprehensive work, divided into three sections, al-usul, al-furu and al-rawda.
The usul give traditions concerning the principles of religion and principles on which religious law is based. The furu' concern the traditions which elaborate the details of religious law, while the rawda is a collection of traditions outlining various points of religious interest and including some of the letters and speeches of the Imams.
One of the principal features of the work is that the traditions are presented systematically in chapters according to their subject matter. This is a system which Islamic scholars had begun to use in the second half of the second century and in the third century of the Islamic era. Al-Kulaini was not the first Imami scholar to use the method. There are other works of traditions which use the same method, notably Kitab al-Mahasin of Ahmad b. Muhammad b. Khalid al-Barqi (d. 274/887). 
However it seems to have been the first work to present such a comprehensive survey of Imami traditions in this manner.
The source collections of traditions were known as usul. These were collections of traditions, either heard directly from the Imam or at least at second hand. There were said to have been four hundred of such collections. 
These traditions were not arranged in chapters according to subject but arranged in the order in which the traditions were heard, regardless of subject matter or which particular Imam they were heard from. 
It was these usul as well as earlier edited collections which were the basis of al-Kulaini's collection as he heard them taught by earlier scholars. Unfortunately with the development of the comprehensive collections, the usul must have become less important, and only a few survive in manuscript.
Traditionists before al-Kulaini and traditionists after him, examined the isnads (chain of authorities) with great care. Their purpose was to make sure that all reporters of a particular tradition were men of true faith; al-Kulaini himself seems to be less concerned with the isnad than with the matn or content of the tradition. Thus he sometimes reports traditions with men in the isnad, who were not strictly speaking disciples of the Imams; sometimes they belong to a different persuasion like the Zaidis, sometimes they are ghulat, extremists in their views. Some men in the isnads are those who regarded one of the earlier Imams as the final Imam and there are even men entirely unconnected with Shi'i views. 
The scholars of tradition elaborated a system of categorising the different traditions according to the level of authenticity of a tradition, in terms of isnad and subject matter.
The number of traditions in al-Kafi is 15,181; 
according to another reckoning 15,176. 
If the traditions reported in different sections are counted, the number is over 1,000 more. Of the basic traditions, 5,072 are considered sound (sahih) by scholars, i.e. first category; 144 are regarded as good (hasan), second category; 178 are held to be trustworthy (muwaththaq), third category; 302 are adjudged to be strong (qawi), fourth category; and 9,484 are considered weak (da'if), fifth category. 
The fact that a tradition is considered weak does not mean that it is not true. What it means is that the scholars of tradition have found some weakness in the tradition, usually one of the persons in the isnad, which suggests the possibility that the tradition might not go back to the Imam as claimed. The science developed by Islamic scholars of tradition in order to examine the isnads and subject matter of traditions is a very specialised study; it involves, in particular, `ilm al-rijal, the study of the backgrounds of individual traditionists who have handed on the tradition.
The usul of al-Kafi are divided into eight kutub or chapters and most of the kutub are divided into abwab or sections. The eight kutub are.
1-Kitab al-'aql wa-'l'jahl,"The Chapter of Reason and Ignorance". This chapter presents the theological distinction between reason and ignorance.
2- Kitab fadl al-'ilm,"The Chapter of the Excellence of Knowledge". In this chapter knowledge ('ilm) is dealt with on the basis of its basic early Islamic meaning of the traditional knowledge of Islam, i.e. knowledge of religion that has been passed on and inherited. In the course of this chapter, sections deal with the methods of approaching Islamic traditional knowledge; the methods of judging the truth of the subject matter of traditions, a description of traditions from the Imams and arguments against the use of personal opinion (ra'y) and analogy (qiyas).
3- Kitab al-tawhid,"The Chapter of Unity". This, as its name suggests, deals with the theology of God.
4- Kitab al-hujja,"The Chapter of the Proof". This deals with the need for man and the world to have "a proof". That "proof" is the Imams, and before them it was the prophets. It also includes an historical section on the Imams.
5- Kitab al-Iman wa-'l-kufr,"The Chapter of Faith and Unbelief". This is a comprehensive survey of the elements of faith (iman) and unbelief (kufr). It includes such important topics as "the pillars of Islam", and it also deals with the difference between faith (iman) and submission to God (Islam).
6- Kitab al-du'a', "The Chapter of Prayer".This does not concern the statutory salat which is also translated "prayer". This chapter deals with personal prayers (du'a') as distinct from the salat which is performed in a prescribed manner at prescribed times. It records prayers recommended by the Imams for a variety of situations and occasions.
7- Kitab al-fadl al-Qur'an, "The Chapter of the Excellence of the Qur'an". The title of the chapter shows that it concerns the advantages that accrue to the believer who recites the Qur'an, as well as advising on the methods of recitation.
8- Kitab al-'ishra,"The Chapter of Companionship". At first sight it seems rather surprising to find such a chapter included in the usul or principles of religion. The main concern of the other chapters has been man's relationship with God. This chapter emphasizes that that relationship with God also encompasses man's relationship with his fellow men.
The furu' of al-kafi are concerned with the elaboration of the details of Islamic law. Islamic law, as is well known, concerns the whole man and his conduct towards God is as much a matter of Islamic law as his conduct towards his fellow men. The furu' contain many more traditions than the usul and there are 26 kutub. It opens in the traditional Islamic manner with the Kitab al-tahara , "The Chapter of Purity", which concerns the ritual purification that is necessary before prayer (salat) and when the state of ritual purity is broken. The next book Kitab al-haid, "The Chapter of Menstruation" concerns one of the important states in which ritual purity is broken, that of menstruation. The third book also concerns a state which breaks ritual purity, that of death and Kitab al-jana'iz, "The Chapter of Funerals" deals with funerals and other matters concerned with burial rites. The Kitab al-salat, "The Chapter of Prayer" outlines the rules for ritual prayer, and also gives details of superrogatory prayer.
Following Kitab al-salat is another pillar of Islam, the alms tax (al-Zakat) paid as a Muslim. After this comes the Kitab al-siyam, "The Chapter of Fasting". Here the rules of the prescribed fast of Ramadan are outlined as well as those of voluntary fasts, and fasts performed as an act of expiation. Kitab al-Hajj, "The Chapter of the Pilgrimage" gives the rules of that great Islamic rite. Al-Kulaini also includes in this chapter a section on visiting the tombs of the Prophet and the Imams (al-Ziarat).
The next chapter Kitab al-jihad presents traditions on the regulations for holy warfare. It is followed by Kitab al-ma'isha which conerns the manner of earning one's living. All sorts of trading problems are treated in this chapter. Marriage (nikah) is the subject of the next book. There are numerous details including a very detailed section on mut'a or temporary marriage. Marriage is naturally followed by the birth of children and the next book deals with what is necessary and what is recommended at that time. Although it deals with a variety of matters concerned with the birth and bringing up of children, it is called Kitab al-'aqiqa. Aqiqa is actually a sacrifice performed on behalf of a seven-day old child. The hair of the child is cut off and its weight in silver given as sadaqa "charity". The Prophet performed this sacrifice on behalf of al-Hasan and al-Husain and Fatima gave away the sadaqa. After marriage and children, the next subject is that of divorce (al-talaq). The different laws concerning divorce are detailed in traditions from the Prophet and the Imams.
Then the different kinds of slaves and the different methods of freeing them are discussed in kitab al-'itq wa'-l-tadbirwa-'l-katiba. The next two chapters concern hunting (said) and ritual slaughter (dhaba'ih). There follow three chapters on daily living: one is concerned with foods (at'ima) another drinks (ashriba), and the third with clothes, ornaments and courteousness (al-ziq wa-'l-tajammul wa-'l-muru'a). After this comes a chapter on domestic animals (dawajin). Two chapters deal with inheritance. The first entitled al-wasaya deals with bequests while the second al-mawarith outlines the ordinary laws of inheritance. The remaining chapters all concern the administration of the law. Kitab al-hudud outlines the circumstances and the manner in which punishments, which have the authority of the Qur'an, and the Prophet should be administered, while al-diyat concerns the laws of blood vengeance and details the compensation that must be given if someone harms another physically. Kitab al-shahadat concerns the requirements for testimony in legal cases, and Kitab al-qada' wa-'l-ahkam outlines the code of behaviour incumbent upon judges and what type of people they should be. The furu closes with a discussion of oaths, vows and the manner of atonement when the former two are broken in Kitab al-aiman wa-l-nudhur wa-'l-kaffarat.
In the rawda of al-Kafi, al-Kulaini does not follow the systematic method he had used in the usul and the furu'. The traditions follow one another in what appears to be a fairly inconsistent order. It certainly lacks the detailed systematic approach that is so obviously present in the other two parts of the book.
In presenting the traditions in al-Kafi, al-Kulaini's main approach seems to have been to let the traditions speak for themselves. He intervenes very little himself. Sometimes he thinks it necessary to explain some discrepancy or apparent inconsistency, but these occasions are very rare. His main contribution to the task has been the massive work of collecting and editing.
The importance of al-Kafi as a work of tradition is considerable. It is regarded as one of the four major works of Shi'i traditions. This has led to considerable number of commentaries being written about it by later writers. The most important of these is Mir'at al-'uqul fi sharh akhbar al al-rasul by al-Majlisi (d. 1110/1698). Other commentators include Mulla Sadr al-Din al-Shirazi (d. 1050/1640), al-Mazandarani (d. 1080/1699), al-Qazwini (d. 1089/1678) and Muhammad Baqir b. Damad (d. 1040/1630). All these commentaries have been published, though most of them nearly a hundred years ago. In addition to these commentaries, there are numerous others, many of which have also been published. 
The great value of al-Kafi to Shi'i Muslims is emphasized by the number of outstanding scholars of their community who have considered it worthwhile to write commentaries on the work. Al-Kafi represents a decisive moment in the collection of traditions from the Prophet and the Imams and their systematic presentation.
1- Cf. 'Ali Akbar al-Ghaffari's introduction to his eight volume edition of al-Kulaini's al-Kafi Teheran, 3rd edition 1388-), I, 9-13
2- Ibid.I 13-14
3- Ibid. I 14
4- Ibid. I 23-24 citing page 8 of al-Kulaini's text.
5- This work has been edited in two volumes by Jalal al-Din al-Husaini and published in Teheran, 1370 A.H.
6- On the Usul, see Agha Buzurg al-Tihrani al-Dhari'a ila tasanif al-Shi'a (Najaf and Teheran, 1963-), II, 125-129.
7- Hashim Ma'ruf al-Hasani Dirasat fi '1-Kafi wa'-l-Sahih (Sur 1968) 137-8
8- Based on a count of the various categories of Traditions given by Agha Buzurg al-Tihrani op.cit. XVII 245.
9- This number is given by Ali Akbar al-Ghaffar'i in his introduction to al-Kafi, I, 28 footnote 3
10- Agha Buzurg al-Tihrani, op.cit., XVII, 245.
11- F. Sezgin, Geshichte des arabischen Schrifttums (Leiden 1967-), I, 541-2.
Taken from: Al-Serat, Vol. 2 (1976), No. 1 Dr. I. K. A. Howard