IDEs and Utilities
Many resources may be helpful when developing C# programs; this chapter lists some of the most useful ones.
If you are running on Windows, you can use Visual Studio Pro, Visual Studio Express (a free version of Visual Studio), or SharpDevelop (a free open source IDE).
If you are running on other systems using the Mono runtime, you can use the MonoDevelop IDE, and there is some support for Mono in SharpDevelop.
Unit Testing and TDD
If you are using TDD or want to do unit testing, three libraries have been popular.1