Lyman Frank Baum's The Wizard of Oz is more than a children's book. It's a commentary on 1890s American economics. Baum supported the free silver movement, which advocated using silver to back the dollar, while the Eastern establishment favored the gold standard. Readers can find political allusions throughout the book. For example, Dorothy, from Kansas, represents America, and her magic slippers are silver (changed to ruby for the 1939 film). The yellow brick road reflects the fancifulness of basing a currency on gold, a metal measured in ounces (abbreviated "oz").

Source: Museum of American Finance, New York, USA