Tales set on other planets are customarily classed as Science Fiction, and indeed most are; but there has long been one type, the planetary romance (a label which dates from the 1970s but refers to a much older phenomenon), which readers have felt belongs at least partly to fantasy, or rather to Science Fantasy. PRs are stories of adventure set almost entirely on the surface of some alien world, with an emphasis on swordplay (or similar), Monsters, telepathy (> Talents) or other under-explained "Magic", and near-human alien civilizations which often resemble those of Earth's pre-technological past (featuring royal dynasties, theocracies, etc.). The hero is usually from Earth, but the means of his or her "translation" to the far planet is often supernatural rather than technological, involving flying carpets, astral projection, angel-power and kindred devices. Spaceships are sometimes mentioned, but the complete lack of interest shown in the mechanics of space travel is one of the principal features distinguishing PR from space opera (which may be fantastic and illogical in its own ways); super-scientific spacecraft and other mighty machines are central to space opera, but rarely feature in planetary romance.
The planetary romance has its main origin in the Lost-Race novels which flourished from the time of H Rider Haggard's first African adventure stories in the 1880s. The conventions of these novels about present-day heroes stumbling upon primitive societies or backward civilizations in remote parts of the globe were crossed with those of the tale of interplanetary travel – e.g., Across the Zodiac (1880) by Percy Greg (1836-1889) and A Plunge Into Space (1890) by Robert Cromie (1856-1907) – and the resultant mix, usually stripped of any utopian/dystopian or sf ideative "content" evolved into the full-fledged romance of derring-do on an exotic planet. (The Ruritanian romances of the 1890s were perhaps also influential.) Early examples of the new formula include Mr Stranger's Sealed Packet (1889) by Hugh MacColl, set on Mars (attained by antigravity machine); a pair of novels by Gustavus W Pope, Journey to Mars (1894) and Journey to Venus (1895); and Pharaoh's Broker (1899) by Ellsworth Douglas (real name Elmer Dwiggins). The last of these shows the blending of genres very clearly: the hero discovers a Mars peopled by Ancient Egyptians, whose civilization has somehow arisen there by a process of "parallel evolution", and he is able to converse with them in Hebrew.
But the PR did not flourish until the opening decades of the new century. More harbingers of the form can be found in such novels as Lieutenant Gullivar Jones: His Vacation (1905; vt Gulliver of Mars 1964 US) by Edwin Lester Arnold, Angilin: A Venite King (1907) by A L Hallen and A Trip to Mars (1909) by Fenton Ash (real name Frank Atkins; 1840-1927), but the first classic of the type – the original, defining, or "template" work of planetary romance – is A Princess of Mars (1912 All-Story; 1917) by Edgar Rice Burroughs. This opening episode in the adventures of John Carter on the red planet known to its inhabitants as Barsoom, has remained constantly in print and has inspired numerous imitations. The love story of Carter and the evidently mammalian but egg-laying Martian princess was spun out in two sequel volumes, The Gods of Mars (1913 All-Story; 1918) and The Warlord of Mars (1913-1914 All-Story; 1919), which in turn gave rise to a series of eight more books, featuring various protagonists in the same, highly variable, dream-like setting. Throughout, the "science" is absurd, the action brisk, the atmosphere beguiling: it all adds up to the ultimate escapist fantasy (> Escapism).
Few of Burroughs's imitators had his flair, but most of them achieved some success in the pulp Magazines of the interwar years. This was the heyday of the planetary romance, and its practitioners included: John U Giesy, in Palos of the Dog-Star Pack (1918 All-Story; 1965) and two sequels; Ralph Milne Farley (real name Roger Sherman Hoar; 1887-1963), in The Radio Man (1924 Argosy; 1948) and two sequels; Otis Adelbert Kline (1891-1946), in The Planet of Peril (1929) and two sequels; Ray(mond King) Cummings (1887-1957) in Tama of the Light Country (1930 Argosy; 1965) and one sequel; Otis Adelbert Kline again in The Swordsman of Mars (1933 Argosy; 1960) and one sequel; Burroughs again, in a new self-imitative series, Lost on Venus (1935) and three sequels; and Robert E Howard in his posthumous Almuric (1939 Weird Tales; 1964). After WWII, the cycle of Burroughsian planetary romances began again, with such late-in-the-day pastiches as Emperor of Mars (1950) by John (Francis) Russell Fearn (1908-1960); Warrior of Llarn (1964) by Gardner F Fox, Warriors of Mars (1965) by Edward P Bradbury (Michael Moorcock), Tarnsman of Gor (1966) by John Norman, The Goddess of Ganymede (1967) by Mike Resnick (1942- ), Zanthar of the Many Worlds (1967) by Robert Moore Williams (1907-1978), Transit to Scorpio (1972) by Alan Burt Akers (Kenneth Bulmer) and Jandar of Callisto (1972) and Under the Green Star (1972) by Lin Carter, all trailing various sequels.
The PR's most important line of evolution after Burroughs was in the sf Magazines. Here, talented writers such as Leigh Brackett and her occasional collaborator Ray Bradbury were to bring the form to its most romantic pitch. Brackett's The Sword of Rhiannon (1949 Thrilling Wonder Stories; 1953) is representative of her stylish best, while Bradbury's famous The Martian Chronicles (fixup 1950; vt The Silver Locusts UK) returns Burroughsian PR to its roots in true sf via a series of moral tales which are as much comments about life on Earth as about any imaginary planetary venue. A lighter, more humorous, version of PR also developed in the sf magazines of the period, reaching book form in such works as Cosmic Manhunt (1954) by L Sprague de Camp, Big Planet (1952 Startling Stories; cut 1957) by Jack Vance and The Green Odyssey (1957) by Philip José Farmer. Many of Vance's subsequent novels have been PRs, as have been a number by de Camp and Farmer.
Thereafter, the history of PR is, by and large, the history of an sf form. In its most serious examples, like Ursula K Le Guin's The Left Hand of Darkness (1969) and Brian Aldiss's Helliconia trilogy (1982-1985), the PR has mutated into sf, and is hence beyond the scope of this encyclopedia. Nevertheless, something of the old Burroughsian spirit of fantasy endures in a number of popular series, notably Marion Zimmer Bradley's Darkover and Anne McCaffrey's Dragonriders of Pern. These are sf at its most romantic and fantastic, though sometimes leavened with feminist themes (> Gender); their popularity has moved numerous younger writers (particularly women) to emulate them – thus ensuring a future for a century-old tradition. [DP]