I watched the Hitchcock movie of the same name when I was about 12 or 13, and it was spooky, but not actually scary. I don't know why I waited all this time to read the book, but now that I have, I'm very glad that I read it. I highly enjoyed this book. The level of suspense is mild and light throughout the first 2/3 of the book, building slowly but steadily- but then during the last third the tension began growing a more rapid pace, and even though I already knew pretty much what was going to happen, I was on the edge of my seat by the time the story reached its climactic reveal. I was pleasantly surprised at how close the book and the screenplay are. I always love when movies are faithful to the source material, the closer the better imo. I think I might read some more by this author in the future.