You’re smarter than you think.
I saw an ad for a book called Brandwashed. The concept of the ad is that companies are trying to sell us things like makeup as if they were drugs. The basic premise of the book is that many brands convince you to spend more than you need to in pursuit of an image or feeling that may be just visual and has no backing substance. (See the bottom of this post for a link to the ad.)
So I don’t need to buy the book. I already know that. You do too.
The moral of this story is that before you spend your hard-earned money on a book that promises to teach you a new concept, read the reviews. You may already know just about everything it has to say.