The collection also includes key Middle English texts, such as the Ancrene Wisse, the Brut Chronicle and Geoffrey Chaucer's Troilus and Criseyde.

Other items include medieval travelogues and maps, apocalypses, bestiaries, one of the oldest pieces of extant written music, and illuminated manuscripts, such as the two giant Romanesque bibles of Bury (c. 1135) and Dover (c. 1150) and the Chronica Majora by Matthew Paris (c.  1250).

In October 2016, Christopher de Hamel announced that an 11th-century Anglo-Saxon psalter (Cambridge, Corpus Christi College, Lib.

The identity of the psalter was supported by a 13th-century stained glass portrait of Becket in Canterbury Cathedral in which he cradles a similarly bound and coloured book under his left arm.

As part of his collection process, Parker employed a number of scholars, scribes, and book artisans to acquire, curate, maintain, and edit his manuscripts.

Stephen Batman, one of Parker's chaplains, boasted to have collected 6,700 books over the course of four years for the Archbishop, though very few of them were selected for the library:"Among whose Bookes remayned, althoughe the moste parte according to the tyme, yet some worthy the viewe and safe kéeping, gathered wythin foure yeares, of Diuinitie, Astronomie, Historie, Phisicke, and others of sundrye Artes and Sciences (as I can truely auouche, hauing his Graces commission wherevnto his hande is yet to be séene) sixe thousand seauen hundred Bookes, by my onelye trauaile, whereof choyse being taken, he most gratiouslye bestowed many on Corpus Christi Colledge in Cambridge.

Writing to William Cecil in 1573, Parker defended his collection of manuscripts as part of his duty to preserve and print "such rare and written authors that came to my hands, until the days of King Henry the VIIIth, when the religion began to grow better."

"[11] In another letter to Cecil from 1565, Parker described the process of supplementing missing pages of text within his manuscripts by having his skilled scribes imitate the style and layout of other medieval models.

"[12] Though he had already been collecting manuscripts for many years, Parker received official support from the Privy Council in 1568 to continue his search for important historical and religious documents throughout the country.

The ground floor, which was until 2006 the college's student library, has been converted into a temperature-controlled, fire-proof vault and separate reading room for visiting academics.

Additionally, there are a few manuscripts with paper pages which are badly damaged by moisture, or those with very fragile bindings, which at present cannot be successfully imaged in their totality.

Additional information was drawn from the supplemental hand-list by Richard Vaughan and John Fines of 1960, and descriptive material provided by the Parker Library for any manuscripts acquired more recently.