As far as I know, there is no book covering RapidMiner. Beside: RapidMiner is a Tool for DataMining, so reading books about Data Mining will help you to get an idea what you can do in general. Then it might be easier to find the right steps in RapidMiner or to ask precise questions to the community.
After my first two weeks of analysis with RapidMiner, I spend the time to read the complete OperatorReference. I forgot a lot (of course), but at least I got a slight idea what is possible and where I can find it ("hm...I have seen something like this before...").
The question for more real-world examples is often asked, but it is the community which should create them and add them to RapidMiner Wiki...
Just a few thoughts...
PS: There are some more tutorials for RapidMiner Plugins, e.g. Web/Text
and Time Series / Stock Analysis (lost the link)