[R] Bootstrap / permutation textbooks

[Peter Soros]

Dear R experts,

I would like to explore if and to what extent bootstrapping and 
permutation statistics can help me for my research (functional brain 
imaging). I am looking for an introductory textbook, rather legible. I 
have statistical knowledge, but I am definitely no statistical or 
mathematical guru.
Do you have suggestions for a useful textbook?

Thanks a lot,
Peter