Having consulted on hundreds of hires, my favorite interview question, one I’ve never heard anyone else use is, When I speak to your last [or present] boss, what is he or she going to say about you?

Since people are trying to cover themselves for anything that boss might say, it’s amazing the things they’ll reveal. They’ll very often tell you things that last boss would never have brought up, even if the last boss would be allowed to deal with a reference which often they aren’t.