Sword and planet is a subgenre of science fantasy that features rousing adventure stories set on other planets, and usually featuring humans as protagonists. The name derives from the heroes of the genre engaging their adversaries in hand-to-hand combat primarily with simple melée weapons such as swords, even in a setting that often has advanced technology. Although there are works that herald the genre, such as Percy Greg's Across the Zodiac (1880) and Edwin Lester Arnold's Lieut. Gullivar Jones: His Vacation (1905; published in the US in 1964 as Gulliver of Mars), the prototype for the genre is A Princess of Mars by Edgar Rice Burroughs originally serialized by All-Story in 1912 as "Under the Moons of Mars".
The genre predates the mainstream popularity of science fiction proper, and does not necessarily feature any scientific rigor, being instead romantic tales of high adventure. For example, little thought is given to explaining why the environment of the alien planet is compatible with life from Earth, just that it does in order to allow the hero to move about and interact with the natives. Native technology will often break the known laws of physics.
The genre tag "sword and planet" was constructed to mimic the terms sword and sorcery, and sword and sandal. The phrase appears to have first been coined in the 1960s by Donald A. Wollheim, editor of Ace Books, and later of DAW Books at a time when the genre was undergoing a revival. Both Ace Books and DAW Books were instrumental in bringing much of the earlier pulp sword and planet stories back into print, as well as publishing a great deal of new, imitative work by a new generation of authors.
There is a fair amount of overlap between sword and planet and planetary romance, although some works are considered to belong to one and not the other. Influenced by the likes of A Princess of Mars yet more modern and technologically savvy, sword and planet more directly imitates the conventions established by Burroughs in the Mars series. That is to say that the hero is alone as the only human being from Earth, swords are the weapon of choice, and while the alien planet has some advanced technology, it is used only in limited applications to advance the plot or increase the grandeur of the setting. In general, the alien planet will seem to be more medieval and primitive than Earth. This leads to anachronistic situations such as flying ships held aloft by anti-gravity technology, while ground travel is done by riding domesticated native animals.
Stories in the sword and planet genre fall primarily into two chronological classes.
The first includes the stories of Burroughs himself and his early imitators, of whom Otis Adelbert Kline was the most significant.
In A Princess of Mars, John Carter, a Confederate officer and soldier, has taken up prospecting in Arizona after the war to regain his fortune. Under mysterious circumstances, he is transported to Mars, called Barsoom by its inhabitants. There he encounters savage and monstrous aliens, a beautiful princess, and a life of adventure and wonder. Burroughs followed up this first book with several more Barsoom stories, and another series that could be considered Sword & Planet, featuring as hero Carson Napier and his adventures on Venus, natively known as Amtor. Burroughs' Pellucidar series could arguably be considered sword-and-(inner) planet, as it follows most of the plot conventions described below.
The second and larger group includes authors who began to write Burroughs pastiches from the mid-1960s to early 1970s. Such authors included Lin Carter and Michael Moorcock. Except for continuations of the extended Dray Prescot and Gor sequences, and occasional parodies of earlier series, not many new works in the genre have appeared from major publishers since 1980. One notable exception are two books written by S. M. Stirling and published by Tor: The Sky People (2006) and In the Courts of the Crimson Kings (2008). However, smaller presses have continued to issue new works in the genre, most notably Wildside Press, primarily through The Borgo Press imprint. In 2007, for example, Wildside/Borgo published a new book in Charles Nuetzel's Torlo Hannis of Noomas series, and printed the Talera trilogy by Charles Allen Gramlich.
Burroughs established a set of conventions that were followed fairly closely by most other entries in the sword and planet genre. The typical first book in a sword and planet series uses some or all of the following plot points:
A tough but chivalrous male protagonist, from Earth of a period not too distant from our own, finds himself transported to a distant world. The transportation may be via astral projection, teleportation, time travel, or any similar form of scientific magic, but should not imply that travel between worlds is either easy or common. The Earthman thus finds himself the sole representative of his own race on an alien planet. This planet is at a pre-modern, even barbaric stage of civilization, but may here and there have remarkable technologies that hint at a more advanced past. There is no obligation for the physical properties or biology of the alien planet to follow any scientific understanding of the potential conditions of habitable worlds; in general, the conditions will be earth-like, but with variations such as a different-colored sun or different numbers of moons. A lower gravity may be invoked to explain such things as large flying animals or people, or the superhuman strength of the hero, but will otherwise be ignored. (A Princess of Mars, however, when it was first written did loosely follow the most optimistic theories about Mars—e.g., those of Percival Lowell who imagined a dying, dried-up Mars watered by a network of artificial canals).
Not long after discovering his predicament, the Earthman finds himself caught in a struggle between two or more factions, nations, or species. He sides, of course, with the nation with the prettiest woman, who will sometimes turn out to be a princess. Before he can set about seriously courting her, however, she is kidnapped by a fiendish villain or villains. The Earthman, taking up his sword (the local weapon of choice, which he has a talent with), sets out on a quest to recover the woman and wallop the kidnappers. On the way, he crosses wild and inhospitable terrain, confronts savage animals and monsters, discovers lost civilizations ruled by cruel tyrants or wicked priests, and will repeatedly engage in swashbuckling sword-fights, be imprisoned, daringly escape and rescue other prisoners, and kill any men or beasts who stand in his way. At the end of the story he will defeat the villain and free the captive princess, only to find another crisis emerging that will require all his wit and muscle, but will not be resolved until the next thrilling novel in the adventures of...!.[tone]
What follows is admittedly incomplete, but is a listing of some of the more important and more remembered representatives of the genre. Some of the dates are reprint dates, not date of original publication.