As far as an overview of the history of psychedelia, it's just too big to cover well.
there are lots of cool books on it, though.
Krautrocksampler that someone linked to earlier, Japrocksampler also by Julian Cope (the Head Heritage website he runs is a great resource as well), another good Krautrock book that came out recently was Krautrock:Cosmic Rock and Its Legacy. If you can find one and don't mind spending some bucks, Acid Archives is a great book. I'm really glad I spent the dough on it. It is geared more to record collectors, though.