A public library, however small, without a catalogue is nothing more than a chaotic pile of books, where users will be lost for words (in more than one sense). Realising this, the Trustees of Leiden University had a catalogue published as early as 1595. This Nomenclator (A 1) can be regarded as the first comprehensive catalogue of a public library collection ever to be printed. The nearly 500 entries in this 108-page catalogue were listed according to the location of the books in the stacks, arranged by discipline and format (See Bertius 1995, introduction).

From 1595 onwards, many catalogues have been published, most of them in print, in recent years also in digital format. The development of the library collections can be reconstructed by analysing its catalogues and archives. For the rich history of Leiden University Library and its collections see Berkvens-Stevelinck 2012. The last printed catalogue that covered all library holdings was published in 1716: Catalogus librorum tam impressorum quam manuscriptorum Bibliothecae Publicae Universitatis Lugduno-Batavae (A 8). This folio volume of 500 pages describes about 10,000 items (still arranged by subject and format), with another 119 pages for the index. A supplement (paginated 501-534) was published in 1741 (A 9).

All catalogues published after 1741 cover only parts of the Leiden holdings. In 1864 the library started to use alphabetical and systematic card catalogues (and discontinued the practice of shelving books according to subject). The card file system was replaced in its turn by the online catalogue in the 1980s. However, special collection and exhibition catalogues keep being published in print or in digital format.