REST is now all set to be the architectural paradigm of choice for designing and implementing scalable services. The RESTful Web Services expose resources through URIs and use the HTTP methods to perform CRUD operations. The REST architectural paradigm not only opens up a lot of possibilities, but also challenges. We will explore these as we progress through the chapters of this book. This chapter gave an introduction to REST, an architectural style for distributed hypermedia systems. In the next chapter, we will explore Resource Oriented Architectures in detail.