In this chapter, we have covered quite a lot of ground in understanding why pattern-oriented software development is a good way to develop modern software. We started the chapter by citing some key principles. We progressed further to demonstrate the applicability of these key principles by iteratively skinning an application that is extensible and resilient to changes. Through this journey, we covered concepts such as the command pattern, factory method pattern, facade pattern, design by contract, template method pattern, XML configuration files, LINQ to XML, and so on.

In the next chapter, we will continue our discussion of patterns by implementing a logging library, which can serialize contents into file, database, or remote network.