The University of Liège Library's books collection is composed of some 2,000,000 print volumes, of which only 60% are catalogued. Most of the uncatalogued books have been published before 1970 and cataloguing these according usual standards and norms would certainly take decades. To decrease the cost of treatments and increase the number of catalogued volumes, the Library developed a light PHP/MySQL application, Scriptorium, that enables non-catalogers (mostly students) to quickly encode the books (ca 3 min. per item) by providing the most essential information. References are then daily exported in MarcXML to the ILS. Scriptorium has been developed to permit to easily create new independent instances for different parallel retro-cataloguing projects and also to be used by other libraries