I don't think I have to tell you the plot line, or that there's a moderately big twist at the end (I probably also don't have to tell you what that twist is), but it's still a pretty fun read.
Having already known where the story was going, I was able to really appreciate the work Bloch put into never lying. The naivete he paints Norman with is superb, the mental acrobatics he goes through to hold up his delusions.
I consider this a part of horror and thriller novel history, because it really was groundbreaking when it first came out. Even Ira Levin, author of Rosemary's Baby and The Stepford Wives, was credits this as one the pioneering works that inspired him. It is hard, in today's society, and when you already have the knowledge of what is coming, to appreciate this book, I think. I would still recommend it to anyone who is a fan of the horror genre.