If you use Entity Framework in Visual Studio 2008 and .NET 3.5, this is the book you want. Programming Entity Framework, 1st Edition offers experienced developers a thorough introduction to Microsoft's core framework for modeling and interacting with data in .NET applications. This hands-on tour provides a deep understanding of Entity Framework's architecture and APIs, and explains how to use the framework in a variety of applications built with Visual Studio 2008 and .NET 3.5.
From the Entity Data Model (EDM) and Object Services to EntityClient and the Metadata Workspace, this highly acclaimed first edition covers it all.
One important note: while many of the lessons from this book will continue to be valuable as you move to .NET 4, the thoroughly revised second edition of Programming Entity Framework (August 2010) specifically targets Visual Studio 2010 and .NET 4 -- where there have been many advancements and additions to the framework.