This article introduces the synoptic catalog, a computerized combination of a hospital library catalog and a bookseller's catalog. Majors Scientific Books and Richmond Memorial Hospital Libraries in Virginia collaborated to develop the model. A logical evolution in catalog theory and practice, the design expands the identification, collocation, and evaluation functions of the traditional library catalog. This article explains the procedures and specifications, including system requirements, record mapping, design details, scope, record transmission, timing, record importing, and file maintenance. The result is a single-interface catalog providing simultaneous and consistent searching of combined information databases. Bookseller records in the synoptic catalog can be modified to indicate library ownership. The synoptic catalog design supports cost-effective collection development and focuses on actual information needs of library users. This report discusses user convenience, budget requirements, publisher advertising, collection development, productivity, and library-bookseller relations. User response to the catalog has been favorable, but improvements are needed.