I had multiple interviews and most of the questions were find out if you liked books and to see if you weren't a flake. Ideally they were looking for temperament, gauging your interest in reading, and if you have a warm personality. Overall, it was very laid back and casual.
One caveat, most of the people that work there are young, under 30. I don't know if older people don't apply or if they are discriminated against for that. There are older workers but they have been there for a long time they are awesome.