The Bavarian State Library is one of Europe’s largest and most important universal libraries, with unique stocks and collections. In this publication celebrating the library’s 450th anniversary, the authors present a view behind the scenes of this ”Treasury of Knovwledge“. Besides historical topics and descriptions of the most important collections, the articles describe current issues and future challenges – for example the whole issue of mass digitalisation, the roles of net-based user services or library marketing. There is also a detailed account of the Library’s role as the central archive and state library of the Free State of Bavaria. As one of the most important collections of source materials in the world, the Bavarian State Library is guardian of a centuries-old cultural heritage and at the same time positions itself as a modern, innovative service centre for the knowledge society. A selected bibliography completes this anniversary volume.