Book (Misadventures in the Interdimensional Black Market)
From Jenny Everywhere Wiki
Before they learned each other's true identity, Tracker-764 gave Darius a book which “explained all about interdimensional things”, (PROSE: Misadventures in the Interdimensional Black Market) one of the books Tracker had been given by the old man when they parted ways. (PROSE: The Mad Cupid of the Euclidean Plane)
