This document provides an overview of REST (Representational State Transfer), including its core concepts and how to build RESTful web services. The key points are: 1) REST uses resources identified by URIs, and representations of those resources can be transferred via HTTP. 2) RESTful services use standard HTTP methods like GET, PUT, POST and DELETE to operate on resources in a stateless and uniform way. 3) Building stateless, cacheable and layered services allows REST architectures to scale up to internet scale.