Abstract : This grant provides a theoretical foundation as to how to support programmers navigation. We develop a theory of information foraging for software maintenance. Then, to test the theory's validity, generality, and scope, we build predictive models, and use them for empirical lab investigations to evaluate our progress. Finally, we develop library modules and tools for use to empirically investigate real-world settings. The resulting theoretical foundation can replace practices of building software maintenance tools ad hoc, enabling principled progress in supporting programmers who maintain today's complex software.