The UBL develop collections which support the needs of faculty and students of the University.
Leiden University Libraries collect, describe, preserve and provide access to a rich and varied record of scientific publications in support of the teaching, research and strategic goals of the university. The Library holds over 5,2 million paper volumes, over a million e-books and hundreds of databases, electronic reference works and digital text and image collections. With close to 3 million journal article downloads per year and more than 44,000 electronic journals full text available, the Library's digital collection continues to grow at a rapid pace.
The Leiden University Libraries has strengths in many distinct collecting areas from collections medieval prayer books to contemporary Asian Art. Of particular note are the collections of Caribbean, Asian and Middle Eastern cultures and languages, Science, Law and Political theory, European History (which includes art history, colonialism, history of science, cartography, pamphlets and history of religions) and European Languages (Italian, English, Slavic Languages and Dutch).
The regular review of library materials is necessary for maintaining a highly qualitative library collection of current interest to users. Subject librarians and curators continuously evaluate parts of the collections to determine whether the collection is serving its users, if there are any gaps and what remains to be done. Methods for evaluation are for example user surveys, user statistics and comparison of the collection with standard bibliographies.