The first place to search for a catalogue is online. The online catalogues page includes full online catalogues for collections catalogued after 2001, plus brief descriptions of many collections catalogued prior to 2001 which point towards the appropriate printed catalogue. Note that many of our most important printed catalogues have now been digitised and are also searchable online. The digitised 'Quarto' series of catalogues cover key early modern collections and the digitised Summary Catalogues cover all collections acquired up to 1975 which were not catalogued in the Quarto series.
If you don't find what you're looking for on the online catalogues pages, it is worth checking the printed, unpublished catalogues in the Rare Books and Manuscripts Reading Room. These cover collections catalogued between 1975 and the introduction of online catalogues in 2001. Brief descriptions of papers can also be found in an unpublished card index which covers manuscripts acquired by the Library between 1975 and 2004 (the card index is kept in Duke Humfrey's Library).
For further information on the Summary, Quarto, and online catalogues, see the General catalogues tab above. For more specific finding aids for different periods or subject areas (e.g. named collections), see the Collections tab above.
You can also email us for advice at firstname.lastname@example.org.