There was a promo for this book on Javaranch recently.
I know nothing about the book, so "perhaps" is all I can answer! But I thought I'd mention that Flex 4 is on the horizon, so if you are thinking about investing in a book you might want to stall a bit, see what Flex 4 ones appear (the allmon one is Flex 4).
The services integration chapter of Flex 4 in Action includes an awesome set of tutorials on how to integrate Flex with J2EE, BlazeDS, LCDS, ColdFusion, and PHP, each are handled separately, using the new data integration wizard that ships with Flash Builder 4. I'm happy to tell you that it is now easier than ever to integrate Flex with Java. I've seen this get way over-complicated very quickly in a lot of books before. If it seems complicated, you're probably looking in the wrong place. The data integration wizard makes it so easy, and you can even use FB4 to generate all your Java DTO and stub classes, along with their respective Flex VO and service classes!
Dan Orlando Adobe Community Professional
Author, Flex 4 in Action (Manning Press)