I finally had some time to finish reading of Programming Entity Framework DbContext by Julia Lerman and Rowan Miller. This book is like the second part of Programming Entity Framework Code First I reviewed last time. I liked this book even more than the first one. Again the book covers exactly what is said in the title because it is definitive guide to using Entity Framework DbContext API. Both books together form an ultimate resource about Entity Framework 4.1 (and newer versions) containing some interesting information not mentioned elsewhere. Authors wrote set of two books providing detailed answers to all commonly asked questions on Stack Overflow and MSDN forum.
Again my biggest complain goes to missing index in the electronic edition of the book bought directly on O'Reilly. It is not a big problem in electronic version but it would be a big disappointment if the index is not present in paper version.
There are still few topics missing in the whole Entity Framework puzzle that are not described in either of these books. These topics include mapping with designer in database and model first approaches which are possible with DbContext API as well. These topics remained same as in Entity Framework 4.0 covered in previous great Entity Framework resource: Programming Entity Framework, 2nd edition by Julia Lerman. Combining new books with few selected topics from the last mentioned book will form a knowledge base we need to learn, understand and successfully use Entity Framework and DbContext.
I found one general suggestion at page 79 where I disagree with the book because it is incomplete. This suggestion describes importance of detaching entities when not using POCOs and claims that detaching is not needed when using POCOs. The suggestion is correct if we use pure POCOs with no lazy loading or change tracking proxies (such classes are used by examples in the book) but in case of proxied POCOs the original importance of detaching entities is still in place.