im no PS guru, which is why i recommend what I have used
i learn new things all the time too, and anyone who has seen the stuff i have designed for people over the past 3 years, im not showing off any killer skills with it.
PS is a great program, and the only book i ever bought was the PS Bible, and while it may cover some more-than-intermediate topics, it also covers ALL of the basics and foundation as well so it leaves room for more mastering of it, if you choose to.
vs the Phosotshop for dummies which basically tells you how to open a document, make one and save it ;)