I just sold a load of wood to the town doctor, and after he’d counted his money, I noticed how well he ate and drank at his table. I asked him how he got to be a doctor, and if I could be a doctor, too.

He said, “Oh yes, that is soon managed. All you need to do is go out and buy yourself an ABC book. You know the kind I mean, the book with the cock on the front cover. Then turn your cart and your two oxen into money and buy yourself some clothes, and everything you can find that pertains to medicine. After that, have a sign painted that reads: I am Doctor Knowall, and nail it over the door of your house.”

Well, that seems easy enough, doesn’t it?

Peasant Named Crabb in Doctor Knowall, Grimms.