LINQ, or Language Integrated Query, is a set of features in .NET 3.5 used for writing structured type-safe queries over local object collections and remote data sources.

LINQ enables you to query any collection implementing the IEnumerable interface, including arrays, lists, XML documents, as well as remote data sources such as tables in SQL Server.

LINQ offers the following important benefits:

• Compile-time type-checking
• Language integration (including IntelliSense support)
• Uniformity across different data sources
• Flexible, powerful, and expressive queries

In order to use LiveLinq effectively, you must be reasonably proficient in LINQ. A deep coverage of LINQ is beyond the scope of this document, but there are several excellent resources available on the subject. We recommend the following:

• "C# 3.0 in a nutshell”, by Joseph and Ben Albahari. O’Reilly, 2007.
• “LINQ in Action”, by Fabrice Marguerie, Steve Eichert and Jim Wooley. Manning, 2008.
• “Programming Microsoft LINQ Developer Reference”, by Paolo Pialorsi and Marco Russo. Microsoft Press, 2008.