L. Frank Baum in the context of "Children's fantasy"

Martin Gardner (October 21, 1914 – May 22, 2010) was an American popular mathematics and popular science writer with interests also encompassing magic, scientific skepticism, micromagic, philosophy, religion, and literature – especially the writings of Lewis Carroll, L. Frank Baum, and G. K. Chesterton. He was a leading authority on Lewis Carroll; The Annotated Alice, which incorporated the text of Carroll's two Alice books, was his most successful work and sold over a million copies. He had a lifelong interest in magic and illusion and in 1999, MAGIC magazine named him as one of the "100 Most Influential Magicians of the Twentieth Century". He was considered the doyen of American puzzlers. He was a prolific and versatile author, publishing more than 100 books.

Gardner was best known for creating and sustaining interest in recreational mathematics—and by extension, mathematics in general—throughout the latter half of the 20th century, principally through his "Mathematical Games" columns. These appeared for twenty-five years in Scientific American, and his subsequent books collecting them.

The canon of a work of fiction is "the body of works taking place in a particular fictional world that are widely considered to be official or authoritative; [especially] those created by the original author or developer of the world". Canon is contrasted with, or used as the basis for, works of fan fiction and other derivative works.

A fictional universe, also known as an imagined universe or a constructed universe, is the internally consistent fictional setting used in a narrative or a work of art. This concept is most commonly associated with works of fantasy and science fiction, and can be found in various forms such as novels, comics, films, television shows, video games, and other creative works.

In science fiction, a fictional universe may be a remote alien planet or galaxy with little apparent relationship to the real world (as in Star Wars). In fantasy, it may be a greatly fictionalized or invented version of Earth's distant past or future (as in The Lord of the Rings).

The public domain (PD) consists of all the creative work to which no exclusive intellectual property rights apply. Those rights may have expired, be forfeit, waived or may be inapplicable. Because no one holds the exclusive rights, anyone can legally use or reference those works without permission.

As examples, the works of William Shakespeare, Ludwig van Beethoven, Miguel de Cervantes, Zoroaster, Lao Zi, Confucius, Aristotle, L. Frank Baum, Leonardo da Vinci and Georges Méliès are in the public domain either by virtue of their having been created before copyright existed, or by their copyright term having expired. Some works are not covered by a country's copyright laws, and are therefore in the public domain; for example, in the United States, items excluded from copyright include the formulae of Newtonian physics and cooking recipes. Other works are actively dedicated by their authors to the public domain (see waiver); examples include reference implementations of cryptographic algorithms. The term public domain is not normally applied to situations where the creator of a work retains residual rights, in which case use of the work is referred to as "under license" or "with permission".

Wicked (known in full as Wicked: The Untold Story of the Witches of Oz) is a musical with music and lyrics by Stephen Schwartz and a book by Winnie Holzman. It is loosely adapted from Gregory Maguire's 1995 novel Wicked: The Life and Times of the Wicked Witch of the West, which itself was based on L. Frank Baum's 1900 novel The Wonderful Wizard of Oz and its 1939 film adaptation. Set in the Land of Oz before and after Dorothy Gale's arrival from Kansas, the musical explores the complex relationship between Elphaba Thropp and Glinda Upland — the future Wicked Witch of the West and Glinda the Good, respectively — as they are tested by their contrasting perspectives, shared love interest, and reactions to the Wizard's corrupt rule, culminating in Elphaba's tragic fall.

Produced by Universal Stage Productions with producers Marc Platt, Jon B. Platt and David Stone, director Joe Mantello and choreographer Wayne Cilento, the original production of Wicked premiered on Broadway at the Gershwin Theatre in October 2003, after completing pre-Broadway tryouts at San Francisco's Curran Theatre in May and June of that year. Its original stars included Idina Menzel as Elphaba, Kristin Chenoweth as Glinda, Norbert Leo Butz as Fiyero, and Joel Grey as the Wizard. Despite mixed reviews, the production won three Tony Awards and seven Drama Desk Awards, while its original cast album received a Grammy Award.

The Royal Book of Oz (1921) is the fifteenth book in the Oz series, and the first to be written after L. Frank Baum's death. Although Baum was credited as the author, it was written entirely by Ruth Plumly Thompson. It was followed by Kabumpo in Oz (1922).

The Reilly and Britton Company, known after 1918 as Reilly & Lee, was an American publishing company of the early and middle 20th century, best known for children's and popular culture books from authors like L. Frank Baum and Edgar A. Guest. Founded in 1904 by two former employees of George M. Hill's publishing company, Frank Kennicott Reilly and Charles Sumner Britton. Reilly continued to lead the company until his death in 1932. Britton left the firm around 1916 to start a new company in New York, and for a time the company was guided by William F. Lee, who died in 1924.

Ruth Plumly Thompson (27 July 1891 – 6 April 1976) was an American writer of children's stories, best known for writing many novels placed in Oz, the fictional land of L. Frank Baum's classic children's novel The Wonderful Wizard of Oz and its sequels.

The Land of Oz is a fantasy world introduced in the 1900 children's novel The Wonderful Wizard of Oz written by L. Frank Baum and illustrated by W. W. Denslow.

Oz consists of four vast quadrants: the Gillikin Country in the north, Quadling Country in the south, Munchkin Country in the east, and Winkie Country in the west. Each province has its own ruler, but the realm itself has always been ruled by a single monarch. According to Dorothy and the Wizard in Oz, the ruler has mostly either been named Oz or Ozma. According to The Marvelous Land of Oz, the current monarch is Princess Ozma.