[PDF] C# in Depth by Jon Skeet

Welcome to the fourth edition of C# in Depth. When I wrote the first edition, I had little idea I’d be writing a fourth edition of the same title 10 years later. Now, it wouldn’t surprise me to find myself writing another edition in 10 years. Since the first edition, the designers of the C# language have repeatedly proved that they’re dedicated to evolving the language for as long as the industry is interested in it.

This is important, because the industry has changed a lot in the last 10 years. As a reminder, both the mobile ecosystem (as we know it today) and cloud computingwere still in their infancy in 2008. Amazon EC2 was launched in 2006, and Google AppEngine was launched in 2008. Xamarin was launched by the Mono team in 2011. Docker didn’t show up until 2013.

For many .NET developers, the really big change in our part of the computing world over the last few years has been .NET Core. It’s a cross-platform, open source version of the framework that is explicitly designed for compatibility with other frameworks (via .NET Standard). Its existence is enough to raise eyebrows; that it is Microsoft’s primary area of investment in .NET is even more surprising.

Through all of this, C# is still the primary language when targeting anything like .NET, whether that’s .NET, .NET Core, Xamarin, or Unity. F# is a healthy and friendly competitor, but it doesn’t have the industry mindshare of C#.