Kafi and the 400 Osoul books

The initial 400 "Osoul" books contained the Shia traditions, and were mainly collected during the lifetime of the Iman Baqer and Imam Sadegh (p.b.u.t).After the time of presence of the Imams (p.b.u.t), the authors of the new 4 main collections of traditions, collected and classified all the traditions of the previous 400 "Osoul" books in their compilations. The book of "Kafi", composed by H.E. grand scholar, Seghat ul-Islam Kolaini (died in 329 A.H./ 87 A.D.) is the most comprehensive of them.* * *