The collection is comprised of ephemera created by the Allen Press, particularly prospectuses for their books. Most of the prospectuses are small broadsides folded for mailing. All of the prospectuses served as samples of the Allens's work and provided detailed information about each book. A reply card and return envelope were usually mailed with the prospectuses. Some orders were directed to the Allens and other orders directed to the Argonaut Bookshop in San Francisco.

The collection also includes ephemera for the Book Club of California and Roxburghe Club of San Francisco as well as envelopes, labels, announcements, exhibit postcards, and correspondence with Margot and H. Richard Archer, the latter of whom was a librarian at the Clark Library in the 1940s and 1950s.