Whether we store information for purposes of control or for the production of knowledge, it doesn't really come to life until it is intelligently linked and combined. If sociologists view information primarily as the raw material for the rational process of knowledge production, the irrational side effects of the information society are at least equally fascinating - information that gets out of control and the mis-information that it produces. Working with and reflecting on how to deal with information in the arts was the subject of four master classes called Making Art of Databases that V2_ initiated in 2002/2003, in collaboration with ZKM (Karlsruhe, Germany), C3 (Budapest, Hungary) and Ars Electronica Center (Linz, Austria). This book is one of the results of this series of master classes for artists, students and scientists. The master classes, each in their own specific way, 'translated' the various aspects of the concept of information for the art practice. All of the master class leaders were artists themselves, often supported by invited theorists for the theoretical sections. Two directions in how we deal with information are of interest in art. Within the museum world, the question is one of how archives and collections may be opened up and, ultimately, made meaningful by using digital media. In order to achieve this, analogue archives and collections must first be digitized and stored in databases. For a digital archive to be dynamic and productive, the objects within the database have to be specified in metadata (information about the information). Then the archives may function as new 'knowledge generators' for both the organization and the public. Artists, however, are interested in the material residing in (digital) archives for quite different reasons, as the reprocessing of archived material gives rise to new ways of making art and to new productions. Within pop music this phenomenon is quite common: it has been an important factor in, for instance, hip hop and digging. Each master class placed its own emphasis. C3's master class in Budapest, led by Lev Manovich, focused on image archives in relation to methods of unlocking and visualization. At ZKM in Karlsruhe, Joel Ryan in his master class addressed the question of how to implement information in electronic music and which methods of visualization are required when playing an electronic instrument. The master class at the Ars Electronica Center in Linz was led by Rafael Lozano-Hemmer, together with Brian Massumi. They focused on unlocking information for tactical purposes (art activism). Offering specific information at selected locations in public space and developing scenarios for interactivity and mobility were the key issues. The last master class, held by Sher Doruff at V2_ in Rotterdam addressed the interdisciplinary art practice where various (media) formats such as image, sound and text are linked, in real time and often online via high bandwidth. Information and knowledge are concepts that are often used gratuitously, without further specification of content. The series of master classes contributes to the defining and mapping of typically art and culture-related issues involved in thinking about and working with information and knowledge. In that, it is a reaction to the often superficial presentation of the information and knowledge society as the next 'ministering angel' for a halting economy or the solution to social and political issues. Information in itself is not all that interesting, but the clustering and combination of information is.