There is a significant number of answers that may interest you on Stackoverflow. Specifically: http://stackoverflow.com/questions/215076/whats-the-best-way-to-b

There is a significant number of answers that may interest you on Stackoverflow. Specifically: http://stackoverflow.com/questions/215076/whats-the-best-way-to-become-familiar-with-a-large-codebase http://stackoverflow.com/questions/215076/whats-the-best-way... Two things I do to familiarize with a code base is to look at how the data is stored. Particularly if its using a database with well named tables I can get some rough ideas of how the system works. Then from there I look at other data objects. Data is easier to understand than behavior. The other is watching the initialization process of the application with a debugger or logger. Along those lines if your lucky (my opinion) and the application uses dependency injection of some sort you can look to see how the components are wired together. Generally there is an underlying framework to how code pieces work together and that generally reveals itself in the initialization process if its not self evident.