Arguing that professional library literature often ignores the problem of evaluating the effectiveness of a library tour or the aids (e.g., audiotape, slides, video, computer programs, handbooks) which may supplement the tour, this article provides a proposed evaluation model for measuring a tour's success. The evaluation of library tours is compared to formal course evaluations, and it is suggested that the critical scrutiny of the tours may serve to justify the faculty status of librarians. It is noted that a focused tour objective which identifies the tour's audience, behavior, conditions under which the current behavior exists, and measures performance is integral to the design of the survey instrument. The University of Nevada-Reno's evaluation form for library instruction is included and three charts provide evaluation results for 1985-1989. (MAB)