This article records tradition as it has been passed down and reported. Its sources are not yet part of the atlas's verified catalogue.
Al-Kulayni compiled Al-Kafi, That Which Suffices, over roughly twenty years, a documented span of sustained work distinct from a text assembled quickly in response to a single occasion. He undertook that compilation specifically during the early decades after the Twelfth Imam's occultation began, a documented historical moment distinct from an ordinary period of settled religious life, when the Twelver Shi'a community had just lost direct access to a living Imam and needed a reliable body of transmitted teaching to lean on in that absence.
Al-Kafi drew together hadith attributed to the Prophet Muhammad and the Twelve Imams and organized them across theology, law, ethics and Quranic exegesis, a documented comprehensive scope distinct from a narrower collection confined to legal rulings alone. That breadth is recorded as deliberate: a community facing the sudden loss of direct guidance needed a single reference spanning belief and practice together, not a specialized text addressed to jurists alone.
That a scholar spent two decades compiling a comprehensive hadith collection specifically to answer the moment when his community's direct line to a living Imam had just closed marks Al-Kafi's own origin as a documented case where a reference work was built to meet a precise historical need rather than assembled as a general project undertaken at leisure.