The document describes COMMIT, a technique for mining crosscutting concerns from software repositories. It analyzes historical changes to code entities and uses statistical clustering based on mutual information to identify concerns. COMMIT addresses limitations of prior techniques by using richer historical data sources and modeling concern composition. A case study on two systems finds COMMIT identifies more unique concerns and complements existing techniques. The document also describes the ODBC data retrieval concern identified as a composite of several sub-concerns.