In her book on writing Ariel Gore uses The Wizard of Oz to illustrate “the classic five-act” structure for a novel. She calls it “the traditional Western male story structure that so much of modern prose relies on.”
Act I : “This is your background … This act shows your character in her known world, in her daily life, in her culture or subculture. This is Dorothy in Kansas before the tornado.”
Act II : “Your character faces a crisis and leaves something that is known for something that is unknown. … This is Dorothy landing in Oz.”
Act III : “This act introduces a complication or further conflict. Here your character faces tests, bumps in the road, a temptation or distraction from the goal. … This is Dorothy crossing a fast-moving river, falling asleep in the poppy field, seeking an audience with the Wizard.”
Act IV : “In this act, it appears that the forces of ‘evil’ will win out, the character will never reach her destination … Total defeat. The Wizard is a fraud.”
Act V : “There is a turn of events … that enables your character to resolve the problem, get to her destination or home again. … Dorothy realizes she has what she needs within herself to get home. Tap, tap, tap.”
Ariel Gore mixes up the original L. Frank Baum novel and the MGM movie adaptation somewhat. There’s no fast-moving river in the movie, but there is in the novel. There is no realization in the novel that Dorothy has always had everything she needs to get home. But it does take a sorceress to tell her the silver shoes will get her there, the very shoes she’s been wearing ever since she shook the dust of the Wicked Witch of the East out of them. Her companions, the Tin Woodman, the Scarecrow, and the Cowardly Lion, are the ones who already had what they needed within themselves.
source:
How to Become a Famous Writer Before You’re Dead
by Ariel Gore
2007. Three Rivers Press / Crown Publishing / Random House