Copyright lawyers speak of the 'idea/expression' dichotomy. Copyright protects the expression of ideas in a particular way, not the idea itself. Courts have taken the view that some ideas are so basic that they really couldn't be expressed in many ways - for instance, you've got many more options open to you if you're writing a poem than you do if you're writing a phonebook. I forget the reasoning in the phonebook cases, but seem to recall that in some of them courts held that mere effort undertaken in collecting information didn't guarantee copyright - how else could you publish a list of names and.numbers...
I think for guidebooks like the Rock guide you might be able to make a similar argument. I think a guidebook like the new Araps book is a different kettle of fish though.
Anyway, even if it is copyrighted you can still use it as a source of information. But obviously that'd be more work than being able to lift the descriptions straight out of it..