I was having a chat with my dad about what the different doctors do at the hospital he worked at, and the subject of D.O.s was brought up. He told me what a D.O. does, and to me it sounded like D.O.s do the same things that an M.D. would. This seemed weird to me, because if both positions did the same job, what would be the point in having M.D.s rather than or D.O.s anyway? My question is "How does a D.O. differ from an M.D., and specifically, what kinds of different cases do you treat?"