Cerebus phonebooks are the paperback collections that Dave Sim has collected his comic book series Cerebus in since 1986. They have come to be known as "phonebooks" as their thickness and paper stock resemble that of phone books. The format had a large influence on alternative comics publishing, and was key in the move from the periodical-centric publishing style that was once dominant.
Starting in 1981, Sim started collecting the Cerebus stories in Swords of Cerebus. Swords collected four issues per volume, each with a backup story and new cover.
High Society had been conceived as one complete story, but Sim had not originally planned for it to be published as one volume. He did so more as an expedient:
I have arrived at this decision for a number of reasons (a) the difficulty involved in keeping each volume of Cerebus in print at all times, (b) the convenience of being able to introduce new fans to Cerebus with two large volumes and (at most) two dozen back issues, (c) a manageable format for someday having all 300 issues available, (d) the opportunity to expand Cerebus' exposure by making it available in bookstores.
Sim published it as one 512-page trade paperback volume in 1986. It was offered exclusively through mail order, and sold out its 6000-copy print run within a year. Its success convinced Sim to drop the Swords collections and republish their contents as one volume as well.
Church & State, at 1200 pages, would have been too unwieldy for one volume, so it was published in two—the first in 1987, before the story was finished.
Jaka's Story was the first to be conceived from the beginning with the end "phonebook" collection in mind. When serialized, it prominently displayed the novel name (Jaka's Story) on the cover, and printed both the current issue of the series and the current issue of the novel—so, for example, the January 1989 issue was numbered both Cerebus #119 and Jaka's Story #6.
In High Society, each issue of Cerebus comprised one chapter of the story, but as the series progressed, Sim came to compose the stories with the collected volumes in mind. This meant that the stories would be serialized in the comic book in twenty-page installments, but with little regard for the per-issue reading experience—sometimes an issue would end mid-scene. Many fans started waiting for the collected volumes to be released, abandoning the monthly series—a phenomenon that came to be known as "The Cerebus Effect".