During a 5-day period in 1990, a total of 1,401 reciprocal borrowers in the North Suburban Library System (NSLS) received questionnaires asking about their choice of library and other aspects of borrowing behavior to provide data on the reciprocal borrowing characteristics and patterns within the system. This survey was designed to identify the major variables for use of the Reciprocal Borrowing Program (RPB) and to determine the relative priorities of importance for individuals using RBP in the system. The variables studied included the reason for the library visit, the sex and age group of the reciprocal borrowers, the peak times for specific types of borrowing, and the correlation between the amount of reciprocal borrowing and a library's collection strength and accessibility. Specific libraries were identified as to their lending/borrowing ratios, as well as the direction of lending flows from the host libraries. Those surveyed indicated which type of media they were more likely to borrow, how they had learned about reciprocal borrowing, and their reactions to and complaints about the reciprocal borrowing feature. The narrative report includes a background statement; an executive summary; the survey instrument; frequency results; brief descriptions of the rationale for the study and the methodology used; an explanation of the study sample; and breakdowns of the data and discussions of the reasons for the library visit and the choice of library, the number of items borrowed, use of multiple libraries, geographic patterns of use, materials borrowed, and sources of knowledge of reciprocal borrowing. Also included in this document are a summary of open-ended comments by respondents, and three appendices: "Meetings with NSLS Library Personnel (a report on focus group meetings with library directors and circulation staff)"; "Open-Ended Comments by Home and Host Libraries"; and "Home Library 'Data Dump.'" The appendices make up the major part (451 pages) of the report. (MAB)