4 hours of interviews with one guy?

Hey everyone!

I've been going through the recruiting process at Microsoft. I had a 1 hour technical interview and made it through that. I'm under the impression that that was the only technical portion of interviews. I know just got scheduled for my next round, and I have 4 hour long interviews on one day. Only one person is listed as the interviewer for all of them.

Should I really expect to talk to just one person about the position for 4 hours in one day? I'm really not sure what all could be covered that needs that much time. The position is a low level (non senior, non management) technical role.

Thanks for any insight!