The provenance, i.e. the origin of printed works, is an important component in the indexing of individual books. After formal and content-based categorisation, this is the third level of indexing depth. Indications of ownership such as supralibros and ex-libris, but also handwritten entries, initials, stamps and dedications provide clues as to the previous owners of printed works and sometimes offer illuminating insights into their reading habits. Might we find traces of their reading in the life and works of (famous) readers? Are there personal remarks in the book that provide hints as to how the material was perceived by the reader? Which books were especially popular among certain circles of readers in particular regions?

Provenance is of particular importance for antiquarian bookshops and bibliophily. It is an essential archiving criterion in securing major bequests. A significant branch of research is concerned with locating stolen cultural goods, or looted art. In the Washington Principles of 1998, the Federal Republic of Germany and 43 other states committed themselves to taking suitable measures to return artworks stolen by the Nazis.