Upon Baum's death, Oz publisher Reilly & Lee commissioned a 19-installment continuation of the series from Ruth Plumly Thompson; long-time Oz illustrator John R. Neill added three more books to the series. Four other books by other authors were added over the years. These books make up the "Famous Forty," often referred to as the canonical works of the Oz canon—though many other Ozian works have been written, some as pastiches or parodies, some of which intended as sincere imitations in the best sense of the word.
The most treasured depiction of Oz in the twentieth century was the 1939Technicolor musical adaptation from Metro-Goldwyn-MayerThe Wizard of Oz. The film was used as a star vehicle for budding starlet Judy Garland, but despite a massive publicity campaign, the movie was only moderately successful in its initial theatrical run. It achieved its iconic status after decades of airings over network television, beginning on November 3, 1956. The viewing audience for the TV premiere, broadcast in full color in the earliest years of that broadcast technology, was estimated at 45 million people. Thus began a tradition. For decades to follow, the movie was aired in the United States on or near Easter. Currently the Turner cable networks hold the television rights, and the film is generally shown during the summer and Christmas seasons. At present, the rights to its public distribution are held by Turner Entertainment (a division of Warner Bros. Pictures). As the present century opens, the film is generally available, digitally restored for private viewing on DVD.