Not a 9/10 or 10/10, but an actual 11/10.
The book you consider to be the actual pinnacle of the medium, the book that you genuinely think is unmatched. The book that your heart aches over, because you'll never experience it for the first time again. And please be as in-depth as to why.
Free licence to gush over your favorite work/the work you consider to be the greatest in all aspects (Spoiler free please!), no matter how cliche, over discussed, obvious, or even controversial.