I think it's a bit of a waste of money to be honest. I bought one last year when I was doing my AS levels. It's ok but personally, I'd rather have a more detailed revision guide. My advice would be to buy a proper revision guide and use that instead. I suppose "AS in a week" is alright for the night before the exam revision but not much else. Try a Revision Express guide. I'm thinking about buying one, they look good. Good Luck!