Members of the DDD Community and the EF team spent considerable time discussing and cross-educating each other these subjects and on the true potential of EF. This had a strong influence in the second version of the EF, called EF 4.0, and the improvements that later crystallized in EF 4.1, which included massive improvements intended to address many of those concerns. EF is still going to evolve to improve the experience and to make it easier to fall into what many like to call the "Pit of Success" of software development. But in EF 4 we already reached an important turning point: When customers pick EF for using it in their applications, they often come to us to ask for best practices, e.g. how to implement things with less and more maintainable code. Many of these customers now learn about concepts like Persistence Ignorance and Testability for the first time in our forums, blogs and conference talks! Therefore we are always looking for ways to disseminate this information. This book is a necessary and great attempt to distill the existing body of best practices for doing DDD with EF. I hope it will be very useful for those customers in need of such kind of guidance.