The Music OCLC Users Group (MOUG), the first and oldest of the OCLC cooperative’s user groups, has spent its 40+ year history working to improve access to music materials in libraries. Often that work has felt like an identity crisis as it sought to reconcile its cataloging-centric origins with its public services evolution. But the dedicated professionals associated with MOUG have kept at it over more than four decades because of the guiding notion that if you can make products and services function well for the complexities of music resources, they will work well for any resources.