I recently read what a blogger said about how she rated books. It got me to thinking about what criteria I use when I rate a book, and I quickly realized my ratings are based solely on engagement. If the book engages me at least 90% of the time, the book is a 5 star. If I'm engaged 80% of the time, it's a 4. Anything between 50 and 80 is a 3 star and I don't normally rate anything below that. I also don't choose books that don't interest me. I don't normally read horror because it scares me (although I read Carrie years and years ago and thought it was fantastic),and I think Steven King is a great guy. If there is subject matter that makes me uncomfortable (rare), I still read, but hurry through those parts. Make me laugh, cry or shock me (or an accumulation of all three) and you're a 5. What criteria do you use when rating a book?