Dorothy only dreams she goes to Oz in the movie. In Baum's book Oz is an actual place. The slippers are silver in Baum's book as they are in Wicked, they only become red when the heat from the spell makes red hot.
The entire song about how she has one eye that stays awake when she sleeps and that water can melt her is pretty much taken from Baums description of the witch in his book (she is not green BTW).
Wicked is sort of a mixture of what we know from the movie and from the original book. In Baum's book Dorothy doesn't accidently hit the witch with water trying to put the scarecrow out, she does it intentionally. The Lion, Scarecrow and Tinman aren't even there.
This is where the ending of Wicked comes from. We don't see the Tinman Lion or Scarecrow when Dorothy's sillouette throws the bucket of water at the witch and she melts. There is no, "Want to play ball scare crow?" and frantic "I'm burning I'm burning!"
Those Blocked: SueStorm. N2N Nate. Good riddence to stupid! Rad-Z, shill begone!