Findings are reported for a project designed to improve subject access to books by augmenting MARC records with subject descriptions. A BOOKS data base, consisting of humanities and social science monographs, was created and made available for online searching. The availability of suitable information in books to produce augmented subject descriptions, costs associated with creating the data base, and benefits derived from searching the data base were explored. Findings include: (1) suitable information to select subject descriptions was available in 90 percent of the books selected for the study; (2) cost of selection and input of subject descriptions was about $5.00 per title with an average computer storage cost of $.30 per record/month; and (3) the average cost of a search was about $14.00 for 20 minutes. A controlled test of 90 searches comparing online searching of MARC and BOOKS records showed more relevant items were retrieved using the BOOKS data base. This greater precision together with lower costs for online searching than MARC searching and the ability to answer some queries not possible using catalog information were seen as the major benefits to be derived from searching BOOKS. Sample records, BOOKS user's manual, and searches conducted for the controlled tests are included in the appendices. (JPF)