This is a great book. In my quest to read all the classic SFF that I can, this book jumped to the top of my to-read list, mostly due to my love for Bladerunner. As it turns out though, they're almost two completely different animals, with Bladerunner actually being a mechanical animal masquerading as a real animal and you not being the wiser until you take it to the vet and find out it's fake.
Okay, that analogy sort of failed on me.
The book is better, is what I'm trying to say, which is not terribly surprising to me (I think the only instance I've ever encountered of the movie being better than the book was The Princess Bride). It just takes all of the themes much further than the movie, as well as having a much deeper sense of paranoia to it, which Dick is great at. One part of this novel which was completely absent from the movie was Mercerism, which is a religion that's basically Facebook on steroids. Seriously, the parallels are chilling, and I love that a SF book from the sixties can still be so relevant in that way.
This story asks a lot of questions, and doesn't provide many answers, which I can appreciate. Life seldom gives answers to any of our questions, and I like that Dick lacks the presumption to think that he has the answers that everyone has been looking for. If empathy is what makes us human, and if a human can feel empathy toward an android, what does that say about androids? What does that say about us? Philip K. Dick didn't know, but he certainly got us thinking about it.