This document discusses different data access technologies in .NET, including LINQ, the ADO.NET Entity Framework, and ADO.NET Data Services. It introduces LINQ as a way to query objects using SQL-like syntax. It describes how LINQ can be used with datasets, entity models, and other data stores. The Entity Framework is introduced as providing LINQ support along with a richer object model and query capabilities. ADO.NET Data Services exposes data through a RESTful API for web and mobile clients.