LINQ to Objects Using C# 4.0 takes a different approach to the subject of
Language Integrated Query (LINQ). This book focuses on the LINQ
syntax and working with in-memory collections rather than focusing on
replacing other database technologies. The beauty of LINQ is that once
you master the syntax and concepts behind how to compose clever queries,
the underlying data source is mostly irrelevant. That’s not to say that technologies
such as LINQ to SQL, LINQ to XML, and LINQ to Entities are
un-important; they are just not covered in this book.