A study was undertaken in 1980-81 to investigate the process of user adaptation to an unfamiliar interactive database search system. Adaptation was defined as performance on, knowledge of, and attitude toward the system being used. The experiment tested 44 students and staff members at the University of Sheffield and Sheffield City Polytechnic in England. Users had three levels of prior computer experience. Each user was trained in one of three command languages with increasing levels of complexity and logical power, and then performed 20 searches of a database consisting of some 580 condensations of news articles appearing in British national newspapers between October 1980 and March 1981. Measures of searcher performance such as recall, precision, and self-evaluation were computed, and attitude questionnaires were also administered. It was found that performance increased with experience and that users appeared to perform best with a language of power and complexity commensurate with their own skills at the time of use; i.e., low power/complexity for inexperienced, high power/complexity for experienced users. The report includes an 18-item bibliography, the text of an online help file, a list of the test questions searched, and sample training handouts and questionnaires. (Author/ESR)