A shill, plant or stooge is a person who helps a person or organization without disclosing that he or she has a close relationship with that person or organization.
Does that fact that he wrote a book for the same publisher constitute ‘a close relationship’? Me thinks no.:::Shill typically refers to someone who purposely gives onlookers the impression that he or she is an enthusiastic independent customer of a seller (or marketer of ideas) that he or she is secretly working for.
The review is detailed. This is not marketing.
What’s your problem?
A book review is a form of literary criticism in which a book is analyzed based on content, style, and merit. A book review could be a primary source opinion piece, summary review or scholarly review. It is often carried out in periodicals, as school work, or on the internet.
And he did just that. He analyzed and recommended it. What do you want?