The Web has seen at least four major advancements in browser technology, about once every five years. Ajax has been around for five years, and we're at the next jump: persistent connections between server and client. Node.js makes it easy to write asynchronous, event-driven applications that serve static, dynamic, and persistent data to clients while using a minimum amount of RAM and CPU time. While other programming environments can accomplish similar things, Node has been built from the ground up to make this kind of programming painless. In this course, you'll learn to install, use, and understand Node by building a real-time geographical tracking system (live demo). We start with simple servers, static requests, and dynamically-generated content and then we explore persistent connections and client-side scripting.