Parallel universes in fictionA parallel universe, also known as a alternate universe, parallel world, or alternate reality, is a hypothetical self-contained plane of existence, co-existing with one's own. The sum of all potential parallel universes that constitute reality is often called a "multiverse". While the five terms are generally synonymous and can be used interchangeably in most cases, there is sometimes an additional connotation implied with the term "alternate universe/reality" that implies that the reality is a variant of our own, with some overlap with the similarly named alternate history.
Alternate historyAlternate history (also alternative history, allohistory, althist, or AH) is a subgenre of speculative fiction in which one or more historical events have occurred but are resolved differently than in actual history. As conjecture based upon historical fact, alternate history stories propose What if? scenarios about crucial events in human history, and present outcomes very different from the historical record. Some alternate histories are considered a subgenre of literary fiction, science fiction, or historical fiction.
Philip K. DickPhilip Kindred Dick (December 16, 1928 March 2, 1982), often referred to by his initials PKD, was an American science fiction writer. He wrote 44 novels and about 121 short stories, most of which appeared in science fiction magazines during his lifetime. His fiction explored varied philosophical and social questions such as the nature of reality, perception, human nature, and identity, and commonly featured characters struggling against elements such as alternate realities, illusory environments, monopolistic corporations, drug abuse, authoritarian governments, and altered states of consciousness.
Science fictionScience fiction (sometimes shortened to SF or sci-fi) is a genre of speculative fiction, which typically deals with imaginative and futuristic concepts such as advanced science and technology, space exploration, time travel, parallel universes, and extraterrestrial life. Science fiction can trace its roots to ancient mythology. It is related to fantasy, horror, and superhero fiction and contains many subgenres. Its exact definition has long been disputed among authors, critics, scholars, and readers.