Parallel universes in fiction

Early examples One of the first science-fiction examples of a parallel universe is Murray Leinster's short story Sidewise in Time, published in 1934. Although Leinster's story was not the first example of parallel universes, it is credited with popularizing the concept. The use of parallel universes as a device in superhero fiction was popularized with the publication of the 123rd issue of The Flash, "Flash of Two Worlds", in 1961. In the issue, the Flashes of Earth-One and Earth-Two, Barry Allen and Jay Garrick, meet, establishing the concept of the DC Comics multiverse. == Associated genres ==

Isekai Isekai is a subgenre of Japanese fantasy light novels, manga, anime, and video games revolving around a normal person being transported to or trapped in a parallel universe. Often, this universe already exists in the protagonist's world as a fictional universe, but it may also be unbeknownst to them. ==Fan fiction==

In fan fiction, parallel universes are commonly used as a setting for a story that departs from the canon of the fictional universe that the fan work is based on. Such works are usually referred to as "alternate universe" works, often abbreviated to "AU". Common motivations for writing such stories are to either explore alternative narrative possibilities not depicted in the original media, or to "fix" plot points which were disliked by the fandom. ==See also==