The problem with any book is that they don't update themselves. I'm pretty good working on a certain class of bikes but I've grown to realize that my knowledge is slowly becoming obsolete. I'd say to try internet websites, like Park Tool but I'm thinking they could stand a more frequent updating on topics like cable pull ratios too.

Another problem with such guides is that they may have good instructions regarding "how to do something" but most aren't much on telling you "what to do". You can pull your hair out struggling with a rear derailleur adjustment but, if the problem is a bent derailleur hanger, they don't tell you that.