Explore the essential technologies that establish LINQ as a unique and important new tool for developers who want to query data. By looking at a series of code samples, attendees will learn that LINQ is integrated, unitive, declarative, hierarchical, extensible, transformative, and composable. These principles illustrate why LINQ has quickly been established as an important new development tool. Other topics covered in the talk include deferred execution, lambda expressions, extension methods, expression trees and the IQueryable<T> and IEnumerable<T> interfaces. The goal of the talk is to give developers a practical understanding of why LINQ is useful, and how it can be used to improve our development process.