I agree with this - 2-3 years ago I bought Linux for Dummies. It looked great, had a copy of Red Hat 5 (I think) and gave loads of step by step info.
I opened the book, put in the disk and then didn't bother with Linux for another 6 months. It was a pants book! all it explained was how to install disk 1. It said disk 2 had stuff on it and didn't refer to it, it said nothing of how to get out of trouble. All it gave was extremely detailed info on how to install the disk it contained and then a really brief and hurried list of commands you may want to use.
Frankly I have learned a lot more from magazines, trying it myself and from forums and websites like this one. Unless you are intending to build a mission critical box, I would suggest you install and play with it, the books can only tell you so much they can't tell you how you
will use that info.
You could also look for your local Linux User Group
- they can help with installs and other stuff you need.