This article discusses the development of an inventory project at Brooklyn College that entailed examining the collection and comparing it to the corresponding records in the online catalog. The procedure became necessary in large part due to problems resulting from the migration to a new, integrated cataloging system in 1987. We needed to deal with (a) books in the catalog that were not on the shelves, (b) books on the shelves that were not in the catalog, and (c) books that lacked circulation information (item records). We used the circulation module of our integrated system to discharge every book, thereby changing its record. An unchanged record indicated a missing book. Missing books were then removed from the catalog. Books on the shelves with no bibliographic record were redeemed and entered into the catalog. Item records were created for those books that needed them. Other errors were also identified and corrected during this time.