The War of the Worlds is a science fiction novel written by H.G. Wells and first published in 1898, which describes a Martian invasion of Earth. It is the first known depiction of an alien invasion of Earth and has had an undeniable influence on the numerous subsequent revisions of this same idea. Wells's novel has been adapted into various media: films, radio programs, video games, comics, and television series.

The novel was adapted by Orson Welles in October 1938 to create a radio serial that caused considerable public alarm at the time. Welles changed some aspects of the plot, including the location of the first Martian landing: Grover's Mill, New Jersey. It was broadcast in the format of an urgent news report (although there was an announcement at the beginning stating that it was fictional, many listeners tuned in after the broadcast had already begun, missing the announcement and believing it to be real). This sparked panic among residents of New Jersey and New York, who believed a real alien invasion of Earth was underway. The naiveté of an audience unfamiliar with television contributed to the success of Welles's stunt, for which he nevertheless had to issue a public apology to his listeners.