Uhhh not a whole lot, I mean I'm not really a theologian, but I can try? There's Christianity, and Judaism, and Islam, those are the big three monotheistic faiths. There are slightly different beliefs and rules, but all of them believe in one God, instead of a pantheon. Christians believe in Jesus, too - he's the son of God, the messiah, and he died for our sins thousands of years ago. Jewish and Islamic people don't believe in him, though. I don't know all the details, but that tends to be where the religions differ. The library probably has a ton of books on this, though.