Book describes creating the application, but more it is focusing on adding new functionalities than to describe technical concept. So after first business module, next are pretty much the same and it doesn't make sense to read them. What is more, author describe code so if you generally understand c# and aren't interested how implementation of constructor of Address class looks like you don't have a lot to read. Basically from middle of the book I just fly it over. Additionally not every code is included :-D. The most interesting (for me) part - synchronization server - client were committed.