I wanted to read this book since the moment I saw the movie, but It was until last week that I read it. Maybe it was better this way, because I didn't remember all the scenes from the movie, only those that are almost imposible to forget like the prom/pig blood scene, or the shower in the school scene. 
 The story is told a lot different from the movie script, and it makes in my opinion a more detailed and complete story, viewed from more angles and points of views. 
 The ending is not entirely like in the movie and although it is slightly weaker or less sadistic, it is more realistic and reflects more effectively what a teenager would do .