Shared world

A shared universe or shared world is a set of creative works where more than one writer (or other artist) independently contributes a work that can stand alone but fits into the joint development of the storyline, characters, or world of the overall project. It is common in genres like science fiction.

It differs from collaborative writing where multiple artists are working together on the same work and from crossovers where the works and characters are independent except for a single meeting.

The term shared universe is also used within comics to reflect the overall milieu created by the comic book publisher in which characters, events, and premises from one product line appear in other product lines in a media franchise.

The term has also been used in a wider, non-literary sense to convey interdisciplinary or social commonality, often in the context of a "shared universe of discourse."

Fiction in some media, such as most television programs and many comic book titles, is understood to require the contribution of multiple authors and does not by itself create a shared universe and is considered a collaborative art form. Incidental appearances, such as that of d'Artagnan in Cyrano de Bergerac, are considered literary cameo appearances. More substantial interaction between characters from different sources is often marketed as a crossover. While crossovers occur in a shared universe, not all crossovers are intended to merge their settings' back-stories and are instead used for marketing, parody, or to explore "what-if" scenarios.

It can become difficult for writers contributing to a shared universe to maintain consistency and avoid contradicting details in earlier works, especially when a shared universe grows to be very large. The version deemed "official" by the author or company controlling the setting is known as canon. Not all shared universes have a controlling entity capable of or interested in determining canonicity, and not all fans agree with these determinations when they occur. A fanon may instead find some degree of consensus within the setting's fandom.

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