The Wonderful Wizard of Oz is a children's novel written by L. Frank Baum (May 15, 1856 ? May 6, 1919) and illustrated by W. W. Denslow. Originally published by the George M. Hill Company in Chicago on May 17, 1900,[nb 1] it has since been reprinted numerous times, most often under the name The Wizard of Oz, which is the name of both the 1902 stage play and the 1939 film version. The story chronicles the adventures of a young girl named Dorothy Gale in the Land of Oz, after being swept away from her Kansas farm home in a storm. Thanks in part to the 1939 MGM movie, it is one of the best-known stories in American popular culture and has been widely translated. Its initial success, and the success of the popular 1902 Broadway musical which Baum adapted from his original story, led to Baum's writing thirteen more Oz books. The original book has been in the public domain in the US since 1956.

Published by George M. Hill Company, the novel's first edition had a printing of 10,000 copies and was sold in advance of the publication date of September 1, 1900. By October 1900, the first edition had already sold out and the second edition of 15,000 copies was nearly depleted.

In a letter to his brother Harry, Baum wrote that the book's publisher, George M. Hill, predicted a sale of about 250,000 copies. In spite of this favorable conjecture, Hill did not initially predict the book would be phenomenally successful. He agreed to publish the book only when the manager of the Grand Opera House, Fred R. Hamlin, committed to making The Wizard of Oz into a play to publicize the novel.[nb 3] After Hill's publishing company became bankrupt in 1901, Baum and Denslow agreed to have the Indianapolis-based Bobbs-Merrill Company resume publishing the novel.

By 1938, over one million copies of the book had been printed.[10] Less than two decades later, in 1956, the sales of his novel grew to 3 million copies in print.

The Wizard of Oz has been adapted to other media numerous times, most famously in the MGM's 1939 film starring Judy Garland. Prior to this version, the book had inspired a number of now-less-well-known stage and screen adaptations, including a profitable Broadway musical and three silent films. The 1939 film was considered innovative because of its songs, special effects, and revolutionary use of the new Technicolor.

The story has been translated into other languages (at least once without permission), and adapted into comics several times. Following the lapse of the original copyright, the characters have been adapted and reused in spin-offs, unofficial sequels, and reinterpretations, some of which have been controversial in their treatment of Baum's characters.