Journal of Artists' Books
"The Journal of Artists' Books provides a platform for both theoretical and creative expression. As a forum for the study of artists' books, JAB publishes critical and theoretical articles, reviews of artists' books and exhibitions, and commentary on conferences and and other book art-related activities. JAB also regularly showcases creative work in the form of artists' statements and artist-designed pages and covers."
(from the JAB web site) The library provides access to JAB electronically and in print (intermittently from 1997 forward) at the Sloane Art Library.
"The Bonefolder, an outgrowth of the Book Arts Web, is a peer-reviewed "open-access" e-journal for bookbinding and the book arts. Since fall of 2004, The Bonefolder has reached a global audience and contributed to the body of knowledge in the book arts both theoretically and practically."
(from the journal's web site)
Umbrella (up to 2005 publicly available)
Umbrella is another of the very few journals that deal specifically with book arts. It features interviews, essays, book reviews, and news about events and exhibits.
A number of more general art journals occasionally feature articles on artists' books, including Art on Paper, Printmaking Today, Afterimage, and many others. Most of these journals are indexed in Art Full Text so searching that database can be the best way to find articles from a broader range of sources.