Software maintenance and evolution are the dominant activities in the software lifecycle. Modularization can separate design decisions and allow them to be independently revolved, but modularization often breaks down and complicated global changes are required. Tool support can reduce the costs of these unfortunate changes, but current tools are limited in their ability to manage information for large-scale software evolution. We argue that the map metaphor can serve as an organizing principle for the design of effective tools for performing global software changes. We describe the design of Aspect Browser, developed around the map metaphor, and discuss a case study of removing a feature from a 500000 line program written in Fortran and C.