Okay, this is probably a dumb question, but what exactly is a hornbook? I know it's supposed to be like a supplement to the casebook or something. It looks an awful lot like a casebook. I've looked at the other supplements like E & E's and stuff. What would be the best thing for someone who is understanding things okay but would like to get more clarification and get a good handle on a 1L class (like Civ Pro)? Thanks.