(d. 915), Ibn M ja (d. 886), and Ab D w d (d. 888). Together these form the ‘six books’ of reference. The Sh ‘a have their own collections of ad th, which they accuse the Sunnis of having deliberately ignored or concealed, which extol the virtues of ‘Al b. Ab lib and the Twelve Im ms . The earliest authoritative collection is Al-k f f ‘Ilm al-D n