As I said I've met Xavier Cazin from ORA France, and he gave me Comprendre XSLT (Understanding XSLT) in case I would get to translate it into english.
I must say that it's an excellent book, in fact the best introduction to XSLT for beginners that I've read so far. The examples sound real (ie not silly things about employees or hello world) and demonstrate a wide array of techniques inside and outside XSLT. If after reading it you still haven't understood what XSLT's about, you're probably hopeless.
I really hope that ORA US will want it translated (it's good, they should) as translating such a good book will be very pleasurable.