This manual provides the steps in planning a post-occupancy evaluation of library facilities to determine how effective the designed environment is for users. Evaluating a building provides a feedback loop to the planning process and can help fine tune the building or help others. The first actions of the planners are to clarify the purpose; gain support and endorsement; determine limitations or constraints; and determine level of efforts. They should also learn where to look and to identify objectives of the evaluation. When designing the evaluation, planners will have to decide where the information will come from and who should be involved in the process. The methodology of the evaluation needs to be chosen and the following methods are described: sampling and statistics; performance measures; questionnaires; interviews; focus groups; diaries; and unobtrusive measures. The manual addresses expert evaluations; sequence of access; staff productivity; hierarchy of use; machine requirements; and physical design considerations. Finally, the processes of conducting the study and reporting of the findings are examined. A planning outline is appended. (Contains 11 references.) (JLB)