Books on this site are reviewed and given ratings based on the Gabriel Scale. See this post for a more in-depth explanation.
Five Gabriels: I loved it!
Four Gabriels: I liked it a lot!
Three Gabriels: It was all right.
Two Gabriels: What the heck is this crap?
One Gabriel: Why was this even published?
Half a Gabriel: This book deserves a little more credit. (NOTE: will never be seen on its own)