The subject matter is substantially theology, church history and the classics, reflecting the lives and interests of the donors. The Derry and Raphoe Diocesan Library is an amalgamation of the Derry Diocesan and Raphoe Diocesan libraries. They were amalgamated in 1881. Each library was stocked through donations and bequests from bishops, learned clerics and gentlmen of the 18th and 19th centuries. The last major donation, approximately 2,000 volumes, was from Rev. C. Seymour in 1883. The Library has been housed in various locations over the centuries and it is fair to say losses have been incurred.
The Derry & Raphoe Diocesan Library consists of approximately 6,500 volumes, the bulk of which are 16th-18th century printings. The Collection is rich in STC and Wing items, it also includes a number of incunabula. Items of note include Albetus Magnus: Compendium theologiae veritatis (1480); the Complutensian polyglot Bible (1522); Ortelius's Geographia (1584) and a first edition of Samuel Johnson's Dictionary (1755).
The Collection consists of approximately 6,500 volumes.
There is a card catalogue for the Collection, compiled by Col. G. V. Hart c.1933, nothing added since has been catalogued. There are also two manuscript ledgers with details of each item listed - subject covered, number of volumes, author/editor, place of origin, date, edition and size. These details are accompanied by additional notes and references.
The Derry & Raphoe Diocesan Library is currently housed in the environmentally controlled Special Collections Room at the Learning Resource Centre of the University of Ulster's Magee campus. The Collection is on long term loan to the University from the Diocese. University maintains and provides access to the collection, but it remains the property of the Diocese of Derry & Raphoe.
The Collection is largely static. It has been accumulated through a combination of deposit/bequest and purchase. There is no particular collection policy or focus in operation.