REST identifies the key architectural principles of why the Web is so prevalent and scalable. The next step in the evolution of the Web is to apply these principles to the Semantic Web and the world of web services. REST offers a simple, interoperable, and flexible way of writing web services that can be very different than the RPC mechanisms like CORBA and WS-* that so many of us have had training in. In the next chapter we will apply the concepts of REST by defining a distributed RESTful interface for an existing business object model.