Alien invasion

It describes a covert invasion by aliens who take on the appearance of human beings and attempt to develop a virulent disease to assist in their plans for global conquest.

It is now seen as the seminal alien invasion story and Wells is credited with establishing several extraterrestrial themes which were later greatly expanded by science fiction writers in the 20th century, including first contact and war between planets and their differing species.

[3] Six weeks after publication of the novel, The Boston Post newspaper published another alien invasion story, an unauthorized sequel to The War of the Worlds, which turned the tables on the invaders.

Many well-known science fiction writers were to follow, including Isaac Asimov, Arthur C. Clarke, Clifford D. Simak, plus Robert A. Heinlein who wrote The Puppet Masters in 1951.

With this type of story, the invaders, in a kind of little grey/green man's burden, colonize the planet in an effort to spread their culture and "civilize" the indigenous "barbaric" inhabitants or secretly watch and aid earthlings saving them from themselves.

Examples include the short story Sentry (1954) (in which the "aliens" described are, at the end, explained to be humans), the video game Phantasy Star II (1989),[9] The Martian Chronicles by Ray Bradbury, the Imperium of Man in the Warhammer 40,000 universe, Invaders from Earth by Robert Silverberg, Ender's Game by Orson Scott Card, and the movies Battle for Terra (2007), Planet 51 (2009), and Avatar (2009).

Aliens from Mars launch an invasion of Earth in H. G. Wells ' The War of the Worlds , as illustrated by Henrique Alvim Corrêa .
In Henry Slesar 's 1958 story The Delegate from Venus , an alien robot cautions that Earth will be destroyed if its people do not learn to live in peace.