What's a midwife??

Ja
I have an appointment and I was told I was going to talk to a midwife 
I'm not completely sure if I'll have one but still I need info on them! 
If any of you moms have one or already have in the past what happens n what do they do??    Because I'm not sure I want one .__. 
Update( I plan on having an epidural And be in the hospital I don't want to do all natrual or home / water birth