This is the first Philip K. Dick book I've read, and I have to say I was a bit surprised. I think I was expecting more of an obvious "mind fuck" type book. What I discovered is that Dick's approach is much more subtle. This was a fascinating look at a seemingly alternate universe (at least now, given the original time of its writing) where a crazy drug pretty much ruins your brain. You really get the full effect of the power of the drug through the main character as he conducts a deep undercover operation. It really twisted my brain into knots considering how we identify ourselves, and how the particular drug in the story distorts your way of thinking.