L. Frank Baum is the American author best known as the creator of the Land of Oz. While he was not a direct producer of Japanese animation, his original literary works have served as the source material for numerous anime adaptations produced decades after his death. Born Lyman Frank Baum on May 15, 1856, in Chittenango, New York, he was a writer, poet, and playwright whose most famous work, The Wonderful Wizard of Oz, was published in 1900. He wrote a total of fourteen novels set in the Oz universe, along with many other fantasy stories, and died on May 6, 1919.

As the original creator of the Oz series, Baum is consistently credited in anime productions that adapt his stories. A primary example is the 1986 television series Oz no Mahou Tsukai, a fifty-two episode anime adaptation of his original work. He is similarly credited as the original creator for Space Oz no Bōken, another anime series based on his books. Beyond full series, his stories have been adapted into segments for anthology programs. He is listed as the original creator for individual episodes of World Fairy Tale Series and World Famous Fairy Tale Series, which dramatized classic stories for Japanese audiences. Another notable film is the 1982 anime movie The Wizard of Oz, which also lists him as the original work's author.

Baum's history as a source for animated adaptations is extensive and includes projects outside Japan. However, there is a distinction to be made between his work and that of his son. The 1933 animated short film The Wizard of Oz is sometimes confused with Baum's legacy, but that film's story credit goes to his son, Frank Joslyn Baum, while L. Frank Baum is credited only for the original novel. In contrast, Japanese productions from the 1980s and 1990s credit him directly for the original source material, reinforcing his status as the foundational author.

The recurring themes found in Baum's original works, such as friendship, courage, and the journey of self-discovery, are consistently carried over into their anime adaptations. The visual identity of these anime, while interpreted through a Japanese artistic lens, ultimately draws from the characters and settings Baum conceived, including Dorothy Gale, the Scarecrow, the Tin Woodman, the Cowardly Lion, and the magical Emerald City.

Within the anime industry, Baum's significance is that of a foundational literary source. While he never personally worked on anime, his American children's novel became a cornerstone for international adaptations. His creation of the Oz universe provided a complete fantasy world that Japanese studios could adapt for television and film, introducing classic Western fairy tale elements to a new generation of viewers in Japan and around the world. His work also extends into the realm of original English-language manga, as he is credited as the original creator for the OEL manga Captive Hearts of Oz, demonstrating the continued cross-cultural influence of his writing.