Do Androids Dream of Electric Sheep? by Philip K Dick (which was later made into the film Blade Runner).
I can see why this book is considered a modern classic, and a seminal sci-fi work. Set in 1992 on an Earth decimated by nuclear war (World War Terminus), humans are encouraged to emigrate to colonies on other planets. One of their incentives is an android slave- completely lifelike. The problem is, some of these androids turn on their masters, which is where bounty hunter Rick Deckard steps in. His job is to "retire" the androids (or "andys"), but this is made difficult because they are so lifelike.I'd say this was a good comment on the nature of humanity, and it shows people questioning themselves. Androids can be given false memories of being born, and having a long life, so some characters begin to doubt themselves, and for some you're not sure unless you keep reading.Definately recommended! I'm going to have to watch Blade Runner at some point now, to see how well it translates to film.
NOTE: I looked this up on Amazon to double-check something, and apparently the version I read (SF Masterowrks) isn't the full text. Can anyone confirm this? Are all the books in the series edited like this? I'm asking because I read I am Legend last year in this series. If it's true I'm a bit disappointed, and will try and get the full versions.