I can recommend the Book "Data Mining - Practical Machine Learning Tools and Techniques" from Ian H. Witten and Eibe Frank.
IMHO this book gives a good practical introduction to data mining. The authors are developing the data mining program Weka which can also be utilised by RapidMiner. So you can most likely use all data mining methods which are described in the book from your RM.
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Answers
http://www.cs.cmu.edu/~tom/mlbook.html
Pattern Recognition and Machine Learning Christopher M. Bishop
http://research.microsoft.com/en-us/um/people/cmbishop/prml/
Both books have ebooks online
I can recommend the Book "Data Mining - Practical Machine Learning Tools and Techniques" from Ian H. Witten and Eibe Frank.
IMHO this book gives a good practical introduction to data mining. The authors are developing the data mining program Weka which can also be utilised by RapidMiner. So you can most likely use all data mining methods which are described in the book from your RM.
This book can be very confusing because not everything is explained.
Be sure to ask questions if you don't understand parts of it.
For example, they mention MDL, minimal description length, for pruning trees, but they do go trough any theory on MDL.