This book is a "mini" language reference on the C# programming language. C# is one of the ".NET" languages, and it is widely used for Web application development (ASP.NET), among other things. We go through all essential features of the modern C# (as of C# 10.0 and C# 11.0 on .NET 6/7) in this book.
Although the book is written in a reference style, you can read it more or less from beginning to end and you should be able to get the overall picture of the modern C# language if you have some prior experience with C# or other similar languages such as C++ or Java.
This book is an (informal) language reference, and not a tutorial. It is not intended for complete beginners.