If you are running 'Vampire: the Masquerade', this is the book for your players. I've used this often by giving it to newer players and letting them explore the book at their own pace. It has a lot of the information from the main rulebook, without the rules getting in the way.
It gives a comprehensive overview of Kindred society, the Traditions, the Court positions and their history. At $2.99 a copy, I'd recommend that everyone at your table buy a copy - no matter how much they might think they know about Vampire. Every time I read this it reminds me of something that has slipped my mind.