ASP.NET is an open source web framework, created by Microsoft, for building modern web apps and services that run on macOS, Linux, Windows, and Docker. It provides a programming model, a comprehensive software infrastructure and various services required to build up robust web applications for PC, as well as mobile devices. One ASP.NET teaches all you need to know about the elements of programming with ASP.NET, including Web Forms, MVC, AJAX, Web Pages, Web API and SignalR. We assume no prior ASP.NET experience, but even experienced programmers will find much that is new.