Preparing for Interview - Books in my PS?!

Hi guys, I know it might be a little cocky to assume I'm getting an interview for Economics, but I'm preparing for it nevertheless.

My question is: If I've included any books on my personal statement (I've mentioned three and probably more in my additional PS), should I try and read through the key parts again? Like is it completely necessary, as in they might want me to talk about very specific parts of the books?

Because the problem is, my Economics teacher lent me one of the books I mentioned in my PS to read, and it is probably sitting on his coffee table as we speak. So I can't reread it, because a copy of it is around £20!!!

I can reread the other ones no problem, but I can only vaguely remember the specifics of the previously mentioned book because I read it all the way back in June.

Maybe I'm stressing myself out too much. Thanks in advance guys.

I'd recommend you do. And also don't forget what you wrote about the book in PS, too. It'd probably depend on HOW you mentioned about it, but it's possible they might have a little chat about it, even if just as an ice-breaker.
Probably it will not affect how they assess you by how you could/couldn't talk about it at the interview, but I know someone who couldn't talk about the book he mentioned in PA when asked because he couldn't remember it, which made him panic and the rest of the interview didn't go very well.
It'd be better to prepare as much as possible to make yourself as comfortable as possible when facing
The interview. One less worry = more relaxed state of mind.