This document describes the rationale and process for automatically generating faceted data for inclusion in descriptive metadata for music resources (e.g., MARC bibliographic and authority records). Over the past several years, MLA has collaborated with Gary Strawn of Northwestern University to develop specifications for generating faceted terms based on the presence of existing legacy metadata (mostly Library of Congress Subject Headings (LCSH)). Although implementation of newly-developed faceted vocabularies by music catalogers in current cataloging has reached a critical mass, the benefits of access to music resources offered by these new vocabularies will not be fully realized until a preponderance of music records in a given database carries these terms. The endeavor described here was prompted by that need.