This study of the Virginia Tech Library collections brings together data on circulation and inhouse use, including that of current periodicals, to assess differences according to kinds of use, variations in measurement technique, and time period. Use of current periodicals is found to be both large and qualitatively different from other kinds of use. Differences between circulation and in-house use are discussed. Despite these differences, circulation and in-house use are generally similar in their subject distribution. The subject distribution of circulation patterns is remarkably stable over time, and can be reliably assessed using short sampling periods.