PMA is a comprehensive configuration management system for APL that manages a large (greater than 3MB) APL program and is implemented in APL in both mainframe and PC environments. The system provides multilevel access for programmers, keeps a complete change history for all APL functions and variables, posts warnings about changes to objects that are in use by others, and allows backing up to previous versions of an object. The user interface is itself APL. The authors attribute a substantial reduction in maintenance costs and a 90 percent drop in the error rate to the use of PMA.