Man La Yahduruhu al-Faqih

The title translates roughly as "for him whom no jurist is present," and Ibn Babawayh al-Qummi, honored by later tradition as Shaykh al-Saduq, wrote the book to live up to it. Where Kitab al-Kafi carried its hadith with full chains of transmission back through named narrators to an Imam, al-Saduq stripped most of those chains out, keeping the rulings themselves and leaving the scholarly work of verifying transmission out of a text meant to be usable directly by an ordinary believer travelling or living far from a qualified jurist. The result reads far more like a practical manual than a work of hadith scholarship. It moves topic by topic through the material a believer actually needs: ritual purity, the details of the five daily prayers, fasting during Ramadan, the pilgrimage to Mecca, marriage contracts, inheritance shares and the handling of ordinary commercial disputes, stated as rulings a reader could apply without first having to weigh competing narrations.

Al-Saduq compiled it in the later tenth century CE, and its plain, applied style set it apart from both Kafi before it and the more argumentative works of Shaykh al-Tusi that would complete the Four Books after it. Modern editions divide the work into roughly seven thousand hadith across four volumes, a scale that made it practical for a working reader in a way the more heavily footnoted Kafi and Tahdhib al-Ahkam were not.

Man La Yahduruhu al-Faqih is conventionally counted third among the Four Books, after Kafi and before Shaykh al-Tusi's Tahdhib al-Ahkam and al-Istibsar, though al-Saduq compiled it independently of al-Tusi's later pair rather than in direct response to them. Its legal content overlaps substantially with Furu al-Kafi, the legal section of Kafi, since both authors drew on much the same pool of transmitted hadith circulating among Twelver scholars in the tenth century, but the two books rarely agree in exact wording or arrangement, giving later jurists two independently compiled witnesses to compare against each other rather than one source repeated twice. Al-Saduq included a preface explaining his selection principles, naming the sources and teachers he trusted, which later commentators have used to assess how the book's comparatively light sourcing should be weighed against Kafi's fuller chains.

In practice the Four Books were never meant to be read alone: a working Twelver jurist deriving a ruling on any given question is expected to consult all four together, along with the biographical and chain-of-transmission literature built up around them over the following centuries, rather than treat any single collection as sufficient by itself.