A Kansas farm girl named Dorothy ends up in the magical Land of Oz after she and her pet dog Toto are swept away from their home by a cyclone.

[5][6] The ground-breaking success of both the original 1900 novel and the 1902 musical prompted Baum to write thirteen additional Oz books, which serve as official sequels to the first story.

Over a century later, the book is one of the best-known stories in American literature, and the Library of Congress has declared the work to be "America's greatest and best-loved homegrown fairytale".

He agreed to publish the book only when the manager of the Chicago Grand Opera House, Fred R. Hamlin, committed to making it into a musical stage play to publicize the novel.

Dorothy Gale is a young girl who lives with her Aunt Em, Uncle Henry, and dog, Toto, on a farm on the Kansas prairie.

The Good Witch tells Dorothy that the only way she can return home to Kansas is to follow the yellow brick road to the Emerald City and ask the great and powerful Wizard of Oz to help her.

The next day, she frees a Scarecrow from the pole on which he is hanging, applies oil from a can to the rusted joints of a Tin Woodman, and meets a Cowardly Lion.

The Scarecrow wants a brain, the Tin Woodman wants a heart, and the Lion wants courage, so Dorothy encourages them to journey with her and Toto to the Emerald City to ask for help from the Wizard.

He appears to Dorothy as a giant head, to the Scarecrow as a lovely lady, to the Tin Woodman as a terrible beast, and to the Lion as a ball of fire, with the intention of scaring them all.

He provides the Scarecrow with a head full of bran, pins, and needles ("a lot of bran-new brains"), the Tin Woodman with a silk heart stuffed with sawdust, and the Lion a potion of "courage".

Dorothy summons the Winged Monkeys and tells them to carry her and Toto home, but they explain they can't cross the desert surrounding Oz.

Instantly, she begins whirling through the air and rolling on the grass of the Kansas prairie, up to the farmhouse, though the silver shoes fall off her feet en route and are lost in the Deadly Desert.

[20] In the introduction to the story, Baum writes that "it aspires to being a modernized fairy tale, in which the wonderment and joy are retained and the heart-aches and nightmares are left out".

[26] To assuage her distress, Baum made his protagonist of The Wonderful Wizard of Oz a girl named Dorothy, and he dedicated the book to his wife.

[36] Local legend has it that Oz, also known as the Emerald City, was inspired by a prominent castle-like building in the community of Castle Park near Holland, Michigan, where Baum lived during the summer.

[41] Although influenced by Carroll's distinctly English work, Baum nonetheless sought to create a story that had recognizable American elements, such as farming and industrialization.

[43] Consequently, Baum combined the conventional features of a fairy tale such as witches and wizards with well-known fixtures in his young readers' Midwestern lives such as scarecrows and cornfields.

[45] Another aspect is the Tin Woodman's funnel hat, which is not mentioned in the text until later books but appears in most artists' interpretation of the character, including the stage and film productions of 1902–1909, 1908, 1910, 1914, 1925, 1931, 1933, 1939, 1982, 1985, 1988, 1992, and others.

Professor Russel B. Nye of Michigan State University countered that "if the message of the Oz books—love, kindness, and unselfishness make the world a better place—seems of no value today", then maybe the time is ripe for "reassess[ing] a good many other things besides the Detroit library's approved list of children's books".

[7] Leonard Everett Fisher of The Horn Book Magazine wrote in 2000 that Oz has "a timeless message from a less complex era, and it continues to resonate".

[53] Two years later, in a 2002 review, Bill Delaney of Salem Press praised Baum for giving children the opportunity to discover magic in the mundane things in their everyday lives.

[56] A new edition from Bobbs-Merrill in 1949 illustrated by Evelyn Copelman, again titled The New Wizard of Oz, paid lip service to Denslow but was based strongly, apart from the Lion, on the MGM movie.

[60] Baum wrote large roles for the Scarecrow and Tin Woodman that he deleted from the stage version, The Woggle-Bug, after Montgomery and Stone had balked at leaving a successful show to do a sequel.

Baum explained the purpose of his novels in a note he penned to his sister, Mary Louise Brewster, in a copy of Mother Goose in Prose (1897), his first book.

The most popular cinematic adaptation of the story is The Wizard of Oz, the 1939 film starring Judy Garland, Ray Bolger, Jack Haley, and Bert Lahr.

[66] In Russia, a translation by Alexander Melentyevich Volkov produced six books, The Wizard of the Emerald City series, which became progressively distanced from the Baum version, as Ellie and her dog Totoshka travel throughout the Magic Land.

[67] In 1974, the story was re-envisioned as The Wiz, a Tony Award winning musical featuring an all-Black cast and set in the context of modern African-American culture.

[71] In 2020, an Esperanto translation of the novel was used by a team of scientists to demonstrate a new method for encoding text in DNA that remains readable after repeated copying.

[75] In a 1964 American Quarterly article titled "The Wizard of Oz: Parable on Populism",[76] educator Henry Littlefield posited that the book served an allegory for the late 19th-century bimetallism debate regarding monetary policy.

In 1971, historian Richard J. Jensen theorized in The Winning of the Midwest that "Oz" was derived from the common abbreviation for "ounce", used for denoting quantities of gold and silver.