Uglies by Scott Westerfield.
Tally can't wait to turn sixteen and become pretty. Sixteen is the magic number that brings a transformation from repellent Ugly into a stunningly attractive Pretty, and catapults you into a high-tech paradise where your only job is to have a really great time. In just a few weeks, Tally will be there.
But Tally's new friend, Shay, isn't sure she wants to be Pretty. She'd rather risk life on the outside. When Shay runs away, Tally learns about a whole new side of the Pretty world - and it isn't very pretty. The authorities offer Tally the worst choice she can imagine: find her friend and turn her in, or never turn Pretty at all. The choice Tally makes changes her world forever.
So, in my opinion, this book had a slow start; little was happening for too long, and just when I was about to give up and call it a day by closing the book for good, it suddenly picked up.
And when I say picked up I mean PICKED UP.
Plot twist after plot twist left me thirsty for more, unable to sleep until I managed to get as far as I could through it until I collapsed from exhaustion. I just managed to finish it today and wow. I mean wow. So many 'No way's' and 'oh my gods' were uttered till the very last page of this book.
So, although I didn't enjoy the first half of the book as much as I would have liked, the last half definitely made up for it, sealing the deal on the fact that I will be running to buy the sequel, Pretties, as soon as possible.