Angular is modular. That is to say that its functionality is wrapped up in modules, known as NgModules, and are themselves libraries. Modules are perfect for lumping code together in an organized way. For instance, there are modules for helping with forms, routing, and communicating with RESTful APIs. Many third-party libraries are packaged as NgModules so you can incorporate them into your Angular applications. Two examples of this are Material Design and AngularFire—we'll be taking a look at both of these libraries in later chapters.