Transfer of the personality or Identity from one body to another is a popular sf theme, whether justified by Cartesian dualism (positing an immaterial personality or soul capable of existing independently of the body) or by the Computer analogy in which the mind is software running on the body's hardware or wetware. The protagonist of A E van Vogt's The World of Ā (August-October 1945 Astounding; rev 1948; rev vt The World of Null-A 1970) lives a serial existence, awakening in a new body when killed; the rationale for this transfer is unclear. A similar limited form of Immortality is central to Jack Vance's To Live Forever (1956) and also to Lord of Light (1967) by Roger Zelazny, in which Cloned bodies and transfer technology make the Hindu doctrine of Reincarnation literally true – including such karmic punishments as transfer into animal form. Usurpers in Lord Valentine's Castle (November 1979-February 1980 F&SF; 1980) by Robert Silverberg have transferred the titular ruler into an unrecognizably different (though healthier) body before the story itself begins. Such technology, stripped of mysticism, moves geriatrics into enhanced soldier bodies in Old Man's War (2005) by John Scalzi. Larry Niven suggests a biological route for transfer in "Rammer" (November 1971 Galaxy), whose protagonist's RNA is extracted and injected into a new body; a similar use of "neurone memory" shifts a terminally injured girl's persona into a chimpanzee body in Peter Dickinson's Eva (1988).
Physical brain transplantation has often been considered in sf, a striking early example being the man-to-elasmosaurus transplant of Wardon Allan Curtis's "The Monster of Lake LaMetrie" (September 1899 Pearson's Magazine). Perhaps the earliest Cinema treatment is the 11-minute French comedy The Monkey Man (1908), featuring an ape-to-man transplant. A B Cox's The Professor on Paws (1926) moves a man's brain to a domestic cat; multiple bizarre transplants occur in Le docteur Lerne, sous-dieu ["Doctor Lerne, Undergod"] (1908; trans anon as New Bodies for Old 1923) by Maurice Renard. Harry Stephen Keeler's Sing Sing Nights (1928) features the transplant of a human brain into the skull of a gorilla. An old woman's and a young woman's brains are swapped in Edgar Rice Burroughs's The Master Mind of Mars (1927 Amazing Stories Annual; 1928). Partial transplant leads to separate personalities inhabiting the same body in Black Friday (1940; vt Friday the Thirteenth). A scientist's brain is transferred to a pet dog in "The Body" (January 1956 Galaxy) by Robert Sheckley. Two women's entire heads are swapped in The Head (1959). The traditional "old brain to young body" transplant is varied with cat-to-human and human-to-cat brain swaps in The Atomic Brain (1963; vt Monstrosity; vt The Brain Snatchers). Robert A Heinlein's I Will Fear No Evil (July-December 1970 Galaxy; 1970) and Roland Puccetti's The Death of the Führer (1972) both involve the placing of an older man's brain – in the latter case Hitler's – in a highly attractive female body. Another, more sophisticated transplant story – woman to shark – is Edward Bryant's "Shark" (in Orbit 12, anth 1973, ed Damon Knight). Mention should also be made of the more mystical fictional tradition that transplanted parts carry some trace or stain of the original owner's personality. A classic film example is Orlacs Hände (1924; vt The Hands of Orlac), with homicidal tendencies inherent in a murderer's hands. There is similar transference via blood serum in William Patrick Kelly's Doctor Baxter's Invention (1912), and via cerebrospinal fluid in Curt Siodmak's Hauser's Memory (1968), filmed as Hauser's Memory (1970). The transplant of a fashion model's brain into a dowdy body is central to the film Who is Julia? (1986).
Aliens and others who "take over" human bodies by various insidious means are a commonplace of Paranoid sf. Examples include Eric Frank Russell's Three to Conquer (August-October 1955 Astounding as "Call Him Dead"; 1955), whose Venusian possessors can "infect" further humans, and Christopher Evans's more metafictionally ambiguous The Insider (1981). In Philip José Farmer's A Private Cosmos (1968; rev 1981) the inimical possessors ("Black Bellers") are AIs which have evolved within devices intended to store and transfer personalities. Peter F Hamilton's Night's Dawn trilogy introduces a Horror trope into Space Opera by having countless humans taken over by the returned dead. A kind of ghost survives across the centuries by repeated transfers in Catherine Webb's Touch (2015) as by Claire North.
Temporary identity transfer is analogous to the supernatural concept of possession, an ability usually ascribed to Psi Powers as in A E van Vogt's The Book of Ptath (October 1943 Unknown; 1947; vt Two Hundred Million A.D.; vt Ptath 1976). However, Frederik Pohl's A Plague of Pythons (1965; rev vt Demon in the Skull 1984) achieves the effect via an Imaginary-Science electronic transmitter. Similar Technology allows the characters of Anne McCaffrey's "Dramatic Mission" (June 1969 Analog) to sojourn temporarily or (as it later emerges) permanently in Alien host-bodies; the titular aliens of Ian Watson's Mockymen (2003) borrow human bodies rendered mindless by Drug side-effects. Temporary possession at random but recurring intervals is central to Robert Silverberg's short, bleak "Passengers" (in Orbit 4, anth 1968, ed Damon Knight). Gene Wolfe's The Book of the Long Sun uses a kind of optical Computer-download. Serial possession via identity transfer is the central gimmick of Quantum Leap (1989-1993).
Another common form of transfer leads to a shared identity whose host accepts (not always willingly) one or more mental passengers. Temporary "Educator tapes" in James White's Hospital Station (coll of linked stories 1962) and its Sector General sequels instil alien medical knowledge but also the quirks of the recorded being's personality. Such personalities of the dead share living minds as their ticket to Immortality in John Brunner's "The Last Lonely Man" (May/June 1964 New Worlds); the protagonist of Charles Harness's The Ring of Ritornel (1968) reverses an unwanted quasi-Upload by downloading the victim into his own mind; various parties vie to acquire the recorded essence of an astute businessman in Robert Silverberg's To Live Again (1969); downloading an inimical Alien "Jart" into oneself in Greg Bear's Eternity (1988) proves, despite elaborate safety precautions, to be unwise. On a grander scale, the Reverend Mothers of Frank Herbert's Dune (fixup 1965) use a mystical, Drug-mediated route to provide each new initiate with the memories of all her predecessors; the Empress of the Twenty Universes in Robert A Heinlein's Glory Road (1963) must similarly take on board the mechanically recorded memories of past rulers; the succession of the Autarchy in Gene Wolfe's The Book of the New Sun (1980-1983 4vols) requires the new incumbent to absorb a legacy of accreted knowledge, plus a Greek chorus of dead Autarchs, by (again suggesting the RNA route) literally eating the newly deceased Autarch's brain.
Reciprocal identity transfer, a significant subtheme in itself, is discussed under Identity Exchange. For transfer of the personality to a digital Computer platform – very fashionable, to the verge of Cliché, in sf since the 1980s – see Upload. [DRL]
see also: Parasitism and Symbiosis; Spooks!.
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