This is the only book I have encountered that describes .NET patterns. This is particularly useful when attempting to gain an understanding of how application architectures differ between .NET and J2EE. The Java patterns are also very interesting, especially when compared with those described in the J2EE design pattern specific books. Note that this book might best be described as "Enterprise Design Patterns for non J2EE systems". Some of the patterns can be used to implement DAOs (perhaps for a BMP entity bean). Many others are not really J2EE compliant (eg Identity Map). To some extent, the patterns would only form part of the J2EE container implementation. (However, "Server Component Patterns" by Volter, Schmid and Wolff provides a better coverage of the design patterns applicable to the design of a J2EE container). This book would certainly be useful to any one wrestling with the "are EJBs useful" question. It provides an excellent description of all the issues that need to be resolved for an industrial strength implementation. Unfortunately, there are many edit problems. For example, The MVC text uses both presentation and view interchangably. In one sentence, a typo causes this to be confused with model ("Fundamentally presentation and view are about different concerns" pg 331) Other problems merely affect the sentence construction. (eg ".. and they people specialize in ..." pg331`) These problems are the only reason that I did not give a 5 star rating.