>>4 That depends on the person, though. If you have the ability and charisma that lets you be your own boss, you can do anything whether you've got a diploma or not. You only need diplomas to work under others. However, few people are like this, and this book (I assume) helps you identify if you are or aren't.
I don't enjoy school, but I wouldn't drop out (mainly because my mom wants me to keep going). I enjoy learning. I don't care if I'm teaching myself or if it's a teacher teaching me. IMO, as long as you have the maturity to want to learn and the money to start up something on your own, there's nothing wrong with dropping out.
There are also situations where you don't need to be in school. If you're good at what you do and your portfolio is good enough, your diplomas and resume aren't going to be as big of a deal. Employers want skilled people, not just people who finished school. You can go through college and still suck at what you do compared to someone who just has that natural skill and determination. Who do you think is going to get the job? The one with the skill - not the one with the diploma.