I have read twist 2, cuhuba is spot on. Actually I think they (twist and twist 2) are both dated, iirc trail braking wasn't even covered in twist 2 (could be wrong, its been a year or so since I have read it last). Sport riding techniques by Nick Ienatsch is a decade newer and IMO is probably the book I would recommend over all the ones I have read.
If you happen to enjoy the technical side of stuff, Sportbike suspension tuning is another great read, and will pay for itself tenfold if you plan on adjusting your own suspension.
Im sure there are some other good books on the shelf, anyone else have some suggestions?
Great thread BTW, (usually) it is the rider that is the limiting factor and not the bike. These books are about 20-25 bucks each and will most definitely help riders of all ages and experience levels hone their skills and become a better rider.