ABC for Book Collectors. John Carter's classic dictionary of book terminology, multiple editions available: Z1006 C37 Rare Books/Special Collections - Reference and also online.
AbeBooks Glossary. Terminology used in the antiquarian book trade to describe books.
Book History Online. This is a database of books and articles on the history of the printed book and libraries worldwide. It is based on the print serial publication Annual Bibliography of the History of the Printed Book and Libraries.
ODLIS - Online Dictionary for Library and Information Science. This is the online edition of the work published by Libraries Unlimited with a number of useful entries for rare books.
SHARP - The Society for the History of Authorship, Reading and Publishing was founded to create a global network for book historians working in a broad range of scholarly disciplines.
Web Resources for the History of the Book. List organised by the Consortium of European Research Libraries. Sites are organised by: Bibliographical Data; History of the Book; Museums; Research Centres; Library Organisations; CERL Members; Itinerary of the Book; Cultural Studies and Other CERL Resources.