I can’t attest to the website, but the person they are referencing has been on the Rachel Ray show, Fox news (local), and the Harry Connick Jr. show.
However, be aware that some businesses use legitimate items from legitimate people/companies and once they get your CC# sign you up for auto renewal of some subscription program. I might track down the book from a reputable source.
A very simple Amazon search shows a few related books by Hanson which might catch your interest. Although they don’t list the book you linked, Amazon might have banned certain things with the word “gun” in them.