If you're going to buy just one of the Tori Amos sheet books, this is definently the one you are looking for. All Tori singles from "Little Earthquakes" to "From the choirgirl Hotel".
I'm not a good piano player, so actually I'm not able to play any of the songs -yet. The closest I can get is "china".
One of my friends, however is a great Piano player so I can tell that some of the songs are simplified, for example Cornflake Girl; but that is very understandable...no one can play the piano like Tori. The interpretions however are very good and I would definently recommend it; both if you are a great piano player or just interested in music.