Eclipse Rich Client Platform will teach you how to create professional and redistributable RCP applications. Part I and II look like a tutorial, but the rest of the book goes far beyond. First, you will create a chat application, adding views, editors, actions, help, integrating a third party library... The style is clear, and the progression is logical. API details are left for Part III, where RCP indispensable components are discussed, and that is where the simple tutorial ends.
Part IV introduces more advanced features like p2, dynamic plug-ins, product configurations for various platforms, testing... I found that this part required more thinking than the rest of the book, but it is invaluable if you aim at making a professional application. The last part is a reference about Eclipse and OSGi.
If you plan to make an Eclipse RCP application, if you have some interest in it or in Eclipse plug-ins, if you just like the Eclipse IDE, this book is for you. You'll learn a lot about the Eclipse architecture, and you will learn it the easy way. I also own another book of the Eclipse Series, Eclipse Plug-ins, 3rd Edition, which I enjoyed a lot. I was not disappointed by Eclipse Rich Client Platform, 2nd Edition. I highly recommend it.