It seems that the Apache Definitive Guide has not been well-received, and I would have to agree. It's not very helpful compared with any other O'Reilly book I've owned. Ratings/reviews on Amazon can partially confirm this.
Just wondering if O'Reilly has any plans to revisit this important topic. In the meantime I've gone with the Apache book by the Expert's Voice (ISBN 1590593006) and am considering other books by this publisher. But I'd like to know if an O'Reilly replacement is coming out so I can check it out.