Amazon seems to be deleting comments for the 5-star reviews, so here's a suggestion - Don't be inflammatory. Ask the reviewer for specifics, like "this seems to be your first and only review on Amazon and you're not a verified purchaser, what did you like so much about this book that caused you to review it". Ask for specific page numbers, recipes, ingredients, etc. Any sane person (i.e. the unsuspecting public who might actually think this is a good book) will read these comments and realize that it's by a paid reviewer.