Non-fiction books that are like the Bible to you? Books that you've checked to remember some facts a few times as opposed to reading them for pleasure.
Non-fiction and Bible don't really go hand in hand. Even if they did, it would be a really graphic book and not really one for pleasure. Maybe you would like history around that time period?
Sort of. It's a real expression (at least in England :P) meaning a "must-have" book, usually related to some subject/profession. For example, I'd consider Everyday Cryptography by Keith Martin the cryptographer's Bible. Even after going through it all, it's helpful for reference.