This might be an unpopular opinion, but any self help book by an author without the appropriate training and credentials. If an author doesn’t have multiple peer reviewed papers on the subject that have been published in reputable scientific journals, then they have no business giving professional psychological, career, parenting, or relationship advice to anyone.

On that note: if you’re a self help enthusiast, do not buy that viral self help book without researching the author first. If all you find is their author website, book interviews, and a few Ted-X talks, then move along.