The document discusses gRPC and ASP.NET Core 3.1. It begins with an introduction to gRPC and then covers various topics like how gRPC works, gRPC-web, using gRPC with Azure, and using gRPC with Xamarin. Some key points discussed include that gRPC uses HTTP/2 and Protocol Buffers, gRPC-web allows browsers to make gRPC calls, and gRPC can be used with Azure App Services via gRPC-web. The document also provides some example resources and demos for working with gRPC.