This isn't the book for the gamers who want a supplement to contain more bitchin' powers and the (apparent) answers to some of the great mysteries of the game setting.
Instead, this is jumping in at the deep end of the desperation, confusion and madness of the end of the world, as the vampires see it. Fourteen and fifteen generations later, the power of Caine's curse is wearing off, and vampires are being created who are more human and less vampire than those who have come before them. They aren't masters of the night, they aren't capable of living as humans. They're pathetic creatures living in fear and ignorance, not even knowing that there's an entire World of Darkness ready to do them in for reasons they won't live long enough to learn.
Instead of the high Gothic opera of most "Vampire: The Masquerade" games, "Time of the Thin Blood" is a squalid, brutish and brutal game supplement that stinks of fear sweat and, along the way, gives reasons for the rest of the vampires to be sweating blood along with the thin-blooded.
And, of course, there are some bitchin' new powers: The thin-blooded can't do much of what more potent vampires can do, but they can do some things that none of their elders (and betters) can do, including make babies. The rules for these half-human/half-vampire dhampires are also given. Would a player want to play one? Not most players in most games. But "Time of the Thin Blood" works best on its own (with the core rulebook, of course) or for the rare player who doesn't want to be a Lestat-like master of the night.
And there's also some answers to the big questions, or at least an apparent answer that poses some bigger questions. The game master-only section at the back tells a brief tale: Something very old and very nasty wakes up in India, the supernatural world rises against it, and the world of VtM changes, getting more desperate and somewhat less populated ...
This is the stuff of nightmares and urban legends. Good stuff. Pick it up.