This is worse when the book is just... anecdotes? Stories about hypothetical clients (or ones they swear exist, but don't), which you can't really port over to yourself.
The thing is, you're never going to get that "manual" from a self-help book. Maybe from a therapist or a coach, but the majority of the work and exploration has to be done by yourself; to the people that feel hopeless, discouraged, depressed and alone (the people who may be buying these books) this is a hard thing to sell, so the authors don't.