LINQ (Language Integrated Query) is a set of features introduced in Microsoft(r) Visual Studio 2008 that extends powerful query capabilities to the language syntax of C# and Visual Basic. LINQ introduces standard, easily-learned patterns for querying and updating data, and the technology can be extended to support potentially any kind of data store.
LINQ provides use of LINQ with .NET Framework collections, SQL Server databases, ADO.NET Datasets, and XML documents.
LINQ Reference Pro explains all of the operators which are using in the LINQ statement and gives proper examples.
Also it provides methods extensions which are able to be used practically in the actual field.
Lots of update will be coming soon.