This is a very short book - a novella rather than a novel - and of course I knew the premise before I started reading. In fact I'm a little surprised that I hadn't read it earlier, it's such a classic. Still, knowing the ending didn't make it any less absorbing or creepy. Although it's a little bit dated in places (cassette tapes!), most of the hints at technology still feel as futurstic as it undoubtedly did when it was written. If you haven't read it, it's worth the (rather short) investment of time.