I am totally in love with Scott Westerfeld's books. This wasn't a strong as the Uglies series, but it still hooked me. The premise is that vampirism is caused by a parasite. Original, huh? Our particular parasite-positive, or "peep", is a guy who got infected on a one-night stand but due to some biological quirk isn't the blood-hungry raving monster that other peeps are. Instead, he helps track down nutty peeps and help them into recovery. But when he goes on a search to track down the peep who infected him, he begins to find a slew of mysteries and oddities that will have you reading way past your bedtime.