Looking for a good reference

I got Ubuntu 7.10 and installed it on my old HP laptop (Pavilion ze1115). I'm now looking for a good desk reference that I can thumb through when I'm putzing about with Ubuntu. Any recomendations? I spent about half an hour at Barnes and Noble looking through some fo the UBuntu books, but just really couldn't decide which would help me the most. What I don't want to do is end up logging on to the Internet (yes, I'm still back in the dinosaur days of dial-up) and reading about it in the ubuntu forums for a while and then having to come back to the laptop for experimentation.