The book you're looking for is, at present time,
Eclipse Rich Client Platform: Designing, Coding, and Packaging Java Applications.
As already stated, it's based on the 3.1 version of eclipse, but my opinion is that it's still good to learn the RCP.
I guess that a new book will come out when the platform evolves enough to get this one outdated.
Prior knowledge of eclipse plugin development could be useful but IMO not a must.
Prior knowledge of SWT and JFace is not necessary to learn the RCP through the book, but it's not detailed therein, so you must look for additional resources once you start developing yourself.
I suppose there is enough stuff to be found on the web on the subject, or you could look for the "SWT/JFace in Action" book.
Bye