A library of key object-oriented programming patterns in action coupled with a demo application that shows them being implemented and put to use. Patterns include those involved in Domain Driven Design, Patterns of Enterprise Architecture and Object-to-Relational Mapping. The project is named Xandria after the Ancient Library of Alexandria, in Alexandria, Egypt. Which was one of the largest and most significant libraries of the ancient world. It functioned as a major center of scholarship from its construction in the 3rd century BC until the Roman conquest of Egypt in 30 BC. The first one is rumoured to have burned down destroying reams of ancient knowledge. Let's hope this digital one doesn't face the same dooooom.