There are approximately 4,750 books printed before 1820 in the Parker Library, of which around 1,075 are from the collection of Matthew Parker. Between April 2003 and April 2006 these books were recatalogued online by William Hale, Parker-Taylor Bibliographer, in a project generously funded by Dr. John Taylor, an old member of the College.

The collection covers a wide range of subjects, but is unsurprisingly particularly strong in sixteenth-century church history and the writings of the Reformers. The new catalogue describes these books for the first time to modern bibliographical standards, with extensive indexing enabling searching by subject, provenance and binder where applicable. A secondary objective of the project was to determine as far as possible which of the books in the collection are from the library of Archbishop Parker and which are from other sources. A list of Parker's printed books was compiled as part of the project, and is now available in the Library; details of other former owners and other material can be found by clicking the links on the right-hand side.

Bibliographical records for the Parker Library's early printed book collection have been incorporated into the University of Cambridge's online union catalogue, Newton