Question:

Where do I find in depth books on the Entity Framework?

Answer:

One of the benefits of being on a product team a Microsoft is you get authors who want you to review their books.

So far to date I've have had 3 different authors send me copies of their Entity Framework books.

Here they are in the order that I received them:

ADO.NET Entity Framework - Unai Zorrilla Castro / Octavio Hernandez / Eduardo Quintas
This book is in Spanish, so I really can't comment on the quality personally, being essentially mono-lingual but Diego my Argentinean colleague recommends it, and that is good enough for me. Still I do like having it on my bookshelf, cause it makes me look all Hi-Brow... so thanks Unai.

Programming Entity Framework - Julie Lerman
I've meet Julie personally a couple of times and I know that she poured her heart into this book. So it is not surprising that it is so thorough, it comes in just shy of 800 pages. Julie's book is packed with useful information and has some very interesting real world samples. Thanks for the book Julie.

Professional ADO.NET 3.5 with LINQ and the Entity Framework - Roger Jennings
I've never met Roger, but he definitely keeps us honest on his blog. His book is a little different from Julie's because it covers more of the things around the Entity Framework, like for example LINQ to XML, LINQ to DataSet etc. I only got this yesterday (thanks Roger) but it definitely looks promising.

As you can see some good choices here...

Good luck with your EF reading