Static analysis tools are useful in extracting information from programs. Maintainers are more likely to be overloaded with information extracted from these analysis tools as programs grow in size. This paper outlines some of the theories and strategies of program comprehension and describes how the various strategies can be realised by a simple browsing tool, PUI {Program Understanding Implement), which allows maintainers to understand the relationships between program elements. The tool is based on a matrix of program relations designed to reflect the multi-dimensional nature of programs. This work is centred on the C programming language.