The OhioLINK consortium and OCLC Research collected and analyzed circulation data for libraries within the consortium. The study, which examines the circulation of 28,475,701 items from more than 100 academic libraries, is the largest and most diverse compilation of academic usage data for books ever collected. The authors outline the study methodology, analyze the data, and offer insights into the consortium wide collection usage. Circulation patterns analyzed include subject and language usage, as well as scattering, obsolescence, and duplication. The study results and conclusions offer valuable insights for library collection planning including library purchasing, storage considerations, and future usage prediction.