Self help books can be a source of great knowledge and inspiration. The world is full of stores about people who changed their lives after reading self help books. However, there are many people who would unscrupulously try to capitalize on this market. They write worthless books, just to sell money.
One way to determine the scammers from the helpers is to access user reviews. Find reviews on a website that is not owned by the author or something trying to sell the book. Determine what most people say about the book. If most people found it helpful, then you can safely assume that you might find this book helpful, as well. More info: self-help book reviews