Piece of Trivia for those of you who do not know....The 1939 film version of the Wizard Of Oz was not the first. Here is the Wikipedia piece on the early films:
The earliest "Oz" film series' were produced by Baum in 1908 and 1914 and twice featured the young silent film actress Mildred Harris. Another series that Baum had nothing to do with, aside from a contractual agreement, appeared in 1910, which may have featured Bebe Daniels as Dorothy. Larry Semon, in collaboration with Frank Joslyn Baum, created a rather well-known but unsuccessful version in 1925. The most famous adaptation is the 1939 film, "The Wizard of Oz", featuring Judy Garland as Dorothy (this, in turn, has been adapted into two separate stage productions, first by Frank Gabrielson (who wrote the 1960 version of The Land of Oz for Shirley Temple), and more recently by the Royal Shakespeare Company's John Kane), but the first stage production, in 1902, used a score that is now forgotten, and not the one heard in the 1939 film, though there have been attempts, mostly in Florida, to revive it. Early film versions of the book include a 1914 film produced by Baum himself entitled His Majesty, the Scarecrow of Oz, which incorporates several incidents from the book—the Scarecrow is first seen hanging on a pole, from which Dorothy rescues him, and the Tin Man is discovered standing rusted in the forest—and a 1925 film, Wizard of Oz, featuring Oliver Hardy as the Tin Woodsman.
Also, the book "The Wizard Of Oz" was only the first of 13 books about the land of Oz. I read the first 3 or 4 of them when I was a kid back in the 60s.