This is a set of .NET classes used to create three basic types of applications: Web-based, client-side (Web Forms) and server-side (Web Services). This technology is called also managed APS and it is known as APS+, because it was derived from Microsoft ASP Web technology.

C# 8.0 and .NET Core 3.0 – Modern Cross-Platform Development: Build applications with C#, .NET Core, Entity Framework Core, ASP.NET Core, and ML.NET using Visual Studio Code, 4th Edition
ASP.NET Core 3 and Angular 9: Full stack web development with .NET Core 3.1 and Angular 9, 3rd Edition
C# in Depth, 4th Edition