The Definitive C# Document
The C# language specification document has always been an excellent (and free) resource, useful for learning the language and supporting it. It’s well-written with clear examples and includes some of the background to the various syntax and keywords. It’s also
Visual Studio 2012
If you have installed a paid-for edition of Visual Studio 2012 (not Express), you can navigate to your Program Files (x86)/Microsoft Visual Studio 11.0/VC#/Specifications/1033 folder, and open CSharp Language Specification.docx.
The C# Language Specification is also available via MSDN. Both locations are documented on Microsoft’s MSDN site: C# Language Specification
C# Language and .NET Versions
The C# Language Specification 5.0 document is version 5.0 of C#, which is standardised as ISO/IEC 23270 and ECMA-334. The language is implemented by Microsoft in the .NET runtime version 4.5, and Visual Studio 2012.