The Covenant of Trombli Holy Books were a trio of sacred texts that belonged to the Covenant of Trombli. The cover of each volume was engraved with the head of a wolf, a ram and a hart, respectively, demonstrating the link between the Covenant and Wolfram & Hart and its Senior Partners. The books were written in Trionic - no one volume was complete without the other two. A passage in one abruptly stopped and continued in the next volume, and completed in the third. The Wolf book can be seen in "Couplet" where Angel and Wesley visit the bookstore.