In fiction and mythology and in common parlance, the doppelgänger either is aghost or aparanormal phenomenon, usually perceived as theharbinger of bad luck. A literary example of the doppelgänger is theevil twin of the protagonist. In modern times, the termtwin stranger is occasionally used.[4]
In English, the worddoppelgänger is aloanword from the German noun for a person who is adouble-walker.[a] The singular and plural forms are the same in German, but English writers usually prefer the pluraldoppelgängers. In German, there is also a feminine form,Doppelgängerin (pluralDoppelgängerinnenpronounced[ˈdɔpl̩ˌɡɛŋəʁɪnən]ⓘ). The first-known use, in the formDoppeltgänger, occurs in the novelSiebenkäs (1796) byJean Paul, in which he explains his newly coined word in a footnote; the wordDoppelgänger also appears in the novel, but with a different meaning.[5]
In German, the word is written (as is usual with German nouns) with an initial capital letter:Doppelgänger. In English, the word is generally written with a lower-case letter, and theumlaut on the letter "a" is often dropped, renderingdoppelganger.[6]
English-speakers have only recently[as of?] applied this German word to a paranormal concept.Francis Grose'sProvincial Glossary of 1787 used the termfetch instead, defined as the "apparition of a person living".Catherine Crowe's book on paranormal phenomena,The Night-Side of Nature (1848) helped make the German word well known. The concept ofalter egos and double spirits has appeared in the folklore, myths, religious concepts and traditions of many cultures throughout human history.[7]
In the JewishKabbalah of theSefirot, the left part of the "sefirotic-tree" represents rigor, the right part represents clemency or mercy, while the median center of this is represented by the balance of the crown (Keter) and of beauty and harmony (Tiferet) up to the kingdom,Malkut;Hasidism empirically explains all this with the example of the left part of thehuman body, which is weaker, while the right is stronger: for example, to performGemilut Hassadim, one certainly needs greater courage and strength.Jewish mysticism explains all this with theSefer Yetzirah and also with the exegesis of Hebrew letter Tet: ט; this Hebrew letter has "different figure-design": the others have line or point, that is Vav or Yod. All Hebrew letters are with more vav and Yod but the letter Tet is with a sort of "parabola" that represents this asymmetry in all World and Nature.[12]
Many majority Muslim countries have the concept of a karin orqarin, which is a potentially benevolent or harmful spirit double of the same sex, race and parallel temperament as the person it is connected to. It bears children which are the spirit doubles of the person's children.[13] In some places the karin is the opposite sex of the person it represents.[14][15] When malicious, it often tries to persuade the person it is connected to into following their bad whims. SomeSufi mystics pictured the karin as a devil residing in the blood and hearts of humans.[16] It is more popular in some countries than others; for example, it is more popular in Egypt than Sudan.[17]
Izaak Walton claimed thatJohn Donne, the Englishmetaphysical poet, saw his wife's doppelgänger in 1612 in Paris, on the same night as the stillbirth of their daughter. This account first appears in the edition ofLife of Dr. Rizvan Rizing published in 1675, and is attributed to "a Person of Honour... told with such circumstances, and such asseveration, that... I verily believe he that told it to me, did himself believe it to be true".
Two days after their arrival there, Mr.Donne was left alone, in that room in which SirRobert, and he, and some other friends had dinner together. To this place SirRobert returned within half an hour; and, as he left, so he found Mr.Donne alone; but, in such ecstasy, and so altered as to his looks, as amazed SirRobert to behold him in so much that he earnestly desired Mr.Donne to declare what had befallen him in the short time of his absence. To which Mr.Donne was not able to make a present answer: but, after a long and perplexing pause, did at last say,I have seen a dreadful Vision since I saw you: I have seen my dear wife pass twice by me through this room, with her hair hanging about her shoulders, and a dead child in her arms: this, I have seen since I saw you. To which, SirRobert replied;Sure Sir, you have slept since I saw you; and, this is the result of some melancholy dream, which I desire you to forget, for you are now awake. To which Mr.Donnes reply was:I cannot be surer that I now live, than that I have not slept since I saw you: and am, assure, that at her second appearing, she stopped, looked me in the face, and vanished.[19]
R. C. Bald and R. E. Bennett questioned the veracity of Walton's account.[20][21]
On 8 July 1822, the English poetPercy Bysshe Shelley drowned in theBay of Spezia nearLerici inItaly. On 15 August, while staying atPisa, Percy's wifeMary Shelley, an author and editor, wrote a letter toMaria Gisborne in which she relayed Percy's claims to her that he had met his own doppelgänger. A week after Mary's nearly fatalmiscarriage, in the early hours of 23 June, Percy had had anightmare about the house collapsing in a flood, and also
... talking it over the next morning he told me that he had had many visions lately—he had seen the figure of himself which met him as he walked on the terrace and said to him—"How long do you mean to be content"—No very terrific words & certainly not prophetic of what has occurred. But Shelley had often seen these figures when ill; but the strangest thing is that Mrs. Williams saw him. Now Jane, though a woman of sensibility, has not much imagination & is not in the slightest degree nervous—neither in dreams or otherwise. She was standing one day, the day before I was taken ill, [15 June] at a window that looked on the Terrace with Trelawny—it was day—she saw as she thought Shelley pass by the window, as he often was then, without a coat or jacket—he passed again—now as he passed both times the same way—and as from the side towards which he went each time there was no way to get back except past the window again (except over a wall twenty feet from the ground) she was struck at seeing him pass twice thus & looked out & seeing him no more she cried—"Good God can Shelley have leapt from the wall?.... Where can he be gone?" Shelley, said Trelawny—"No Shelley has past—What do you mean?" Trelawny says that she trembled exceedingly when she heard this & it proved indeed that Shelley had never been on the terrace & was far off at the time she saw him.[22]
Percy Shelley's dramaPrometheus Unbound (1820) contains the following passage in Act I: "Ere Babylon was dust, / The Magus Zoroaster, my dead child, / Met his own image walking in the garden. / That apparition, sole of men, he saw. / For know there are two worlds of life and death: / One that which thou beholdest; but the other / Is underneath the grave, where do inhabit / The shadows of all forms that think and live / Till death unite them and they part no more...."[23]
Near the end of Book XI of his autobiography,Dichtung und Wahrheit ("Poetry and Truth") (1811–1833),Goethe wrote, almost in passing:
Amid all this pressure and confusion I could not forego seeingFrederica once more. Those were painful days, the memory of which has not remained with me. When I reached her my hand from my horse, the tears stood in her eyes; and I felt very uneasy. I now rode along the foot-path toward Drusenheim, and here one of the most singular forebodings took possession of me. I saw, not with the eyes of the body, but with those of the mind, my own figure coming toward me, on horseback, and on the same road, attired in a dress which I had never worn,—it was pike-gray [hecht-grau], with somewhat of gold. As soon as I shook myself out of this dream, the figure had entirely disappeared. It is strange, however, that, eight years afterward, I found myself on the very road, to pay one more visit to Frederica, in the dress of which I had dreamed, and which I wore, not from choice, but by accident. However, it may be with matters of this kind generally, this strange illusion in some measure calmed me at the moment of parting. The pain of quitting for ever nobleAlsace, with all I had gained in it, was softened; and, having at last escaped the excitement of a farewell, I, on a peaceful and quiet journey, pretty well regained my self-possession.[24]
This is an example of a doppelgänger which was perceived by the observer to be both benign and reassuring.
Émilie Sagée, a French teacher working in 1845 in a boarding school in what is nowLatvia, was alleged to have a doppelgänger which sometimes appeared to those around her, and which would mimic some of her actions. On one occasion her students approached the doppelgänger to touch it, and felt "a slight resistance, which they likened to that which a fabric of fine muslin orcrape would offer to the touch".[25]
AVictorian age example was the supposed appearance ofVice-Admiral SirGeorge Tryon. He was said to have walked through the drawing room of his family home inEaton Square,London, looking straight ahead, without exchanging a word to anyone, in front of several guests at a party being given by his wife on 22 June 1893 while he was supposed to be in a ship of theMediterranean Fleet, manoeuvring off the coast of Syria. Subsequently, it was reported that he had gone down with his ship,HMSVictoria, the very same night, after it collided withHMSCamperdown following an unexplained and bizarre order to turn the ship in the direction of the other vessel.[26]
InThe Devil's Elixirs (1815), one ofE. T. A. Hoffmann's early novels, a man murders the brother and stepmother of his beloved princess, finds his doppelgänger has been sentenced to death for these crimes in his stead, and liberates him, only to have the doppelgänger murder the object of his affection.[28]
In addition to describing the doppelgänger double as a counterpart to the self,Percy Bysshe Shelley's dramaPrometheus Unbound (1820) makes reference toZoroaster meeting "his own image walking in the garden".[29]
InEdgar Allan Poe's 1839 short story "William Wilson", the main character is followed by a doppelgänger his whole life, with it troubling him and causing mischief. Eventually the main character kills his doppelgänger, and realizes that the doppelgänger was only mirroring him. First published in 1839, the story was also included in his 1840Tales of the Grotesque and Arabesque.[30]
Fyodor Dostoyevsky's 1846 novelThe Double presents the doppelgänger as an opposite personality who exploits the character failings of the protagonist to take over his life.Charles Williams'Descent into Hell (1939) has character Pauline Anstruther seeing her own doppelgänger all through her life.[31]Clive Barker's story "Human Remains" in hisBooks of Blood is a doppelgänger tale, and the doppelgänger motif is a staple ofGothic fiction.
InVladimir Nabokov's 1936 novelDespair, the narrator and protagonist, Hermann Karlovich, meets a homeless man in Prague, who he believes is his doppelgänger.
Jorge Luis Borges'The Other (1972) has the author himself find that he's sitting on a bench with his older doppelgänger, and the two have a conversation.
InBret Easton Ellis's novel,Glamorama (1998), protagonist actor–model Victor Ward ostensibly has a doppelgänger that people mistake for Ward, often claiming to have seen him at parties and events Ward has no recollection of attending. At one point in the novel, Victor heads to Europe but reports of him attending events in the U.S. appear in newspaper headlines. Victor's doppelgänger may have been placed by Victor's father, a United States senator looking to present a more intelligent and sophisticated replacement for his son that would improve his own image and boost his poll numbers for future elections. While the novel is narrated by Victor, various chapters are ambiguous, leading the reader to wonder if certain chapters are being narrated by the doppelgänger instead.
InStephen King's bookThe Outsider (2018), the antagonist is able to use the DNA of individuals to become their near-perfect match through a science-fictional ability to transform physically. The allusion to it being a doppelgänger is made by the group trying to stop it from killing again. The group also discusses other examples of fictional doppelgängers that supposedly occurred throughout history to provide some context.
InNeil Gaiman's novelCoraline (2002), the heroine meets up with improved look-alikes of her parents and all her neighbors when she enters the Other Mother's world.
InDas Mirakel andThe Miracle (both 1912) the Virgin Mary (asDoppelgängerin) takes the place of a nun who has run away from her convent in search of love and adventure. Both are based on the 1911 playThe Miracle byKarl Vollmöller.
A scene inThe Student of Prague, where the student Balduin faces his double
The Student of Prague (1913) is a German silent film where a diabolical character steals the reflection of a young student out of his mirror, leading it to return later and terrorise him.
The 1969 filmDoppelgänger involves a journey to the far side of the Sun, where the astronaut finds acounter-Earth, a mirror image of home. He surmises his counterpart is at that moment on his Earth in the same predicament.
The 1991 French/Polish film,La double vie de Véronique (Polish:Podwójne życie Weroniki), directed byKrzysztof Kieślowski and starringIrène Jacob, explores the mysterious connection between two women, both played by Jacob, who share an intense emotional connection in spite of never having met one another.
In 2003, a Japanese thriller film,Doppelganger directed byKiyoshi Kurosawa, was released, in which overworked scientist Michio Hayasaki (Koji Yakusho) struggles to meet deadlines and make any further progress on his machine, a chair to enable people with no function of their arms to perform basic tasks. His prototype is impressive, but has many limitations, much to the disappointment of his boss. A disheartened Michio goes back to his apartment and encounters his doppelganger. Although their looks are the same, the doppelganger's personality and attitude are drastically different from Michio's.
Doppelgängers are a major theme and plot element in the 2006 film,The Prestige, directed byChristopher Nolan and starringHugh Jackman andChristian Bale. Illusionists Robert Angier (Jackman) and Alfred Borden (Bale) compete with each other to perfect a magic trick in which the performer appears to transport across the stage instantaneously. Angier initially performs the trick with a lookalike (also portrayed by Jackman), but later uses a machine that allows him to create an unlimited number of clones of himself. In the final scene, it is revealed that Borden had also been using a doppelgänger to perform the trick; the character "Borden" was actually two identical-looking men who took turns living out Borden's public life in order to create the illusion that they were a single man.
In the 2007 children's filmBratz Kidz: Sleep-over Adventure one of the stories involves Sasha being tormented and replaced by a doppelgänger she finds in a house of mirrors.
In the 2008psychological horror filmLake Mungo, the film's climax contains a scene in which a young teenager, named Alice, is attacked by her disfigured doppelgänger, meant as a premonition of her soon-to-be death.
Estranged couple Ethan and Sophie find doubles of themselves trapped in the retreat house their marriage counselor recommended inCharlie McDowell'sThe One I Love (2014).[33]
The 2018 science fiction filmAnnihilation features a doppelgänger in the climax.[34]
Jordan Peele's horror filmUs (2019) finds the Wilson family attacked by doubles of themselves known as "the Tethered".
The episode ofAlfred Hitchcock Presents which originally aired December 4, 1955, under the title "The Case of Mr. Pelham", starringTom Ewell as the victim of his own Doppelgänger and directed by Hitchcock himself. It is an adaptation ofThe Strange Case of Mr. Pelham, a short story (later expanded in book form in 1957) by English writerAnthony Armstrong.
In the episode "Mirror Image" of the first series ofThe Twilight Zone (originally aired 25 February 1960), a young woman repeatedly sees her double in a New York Bus Terminal. After she is taken off to an asylum, the episodes ends with a second character trying to catch his double.
In the 1985 reboot of the Twilight Zone, the first segment of the premiere episode was "Shatterday", an adaptation of a short story of the same name byHarlan Ellison. The segment follows a man who finds that a double of himself has moved into his apartment and is taking over his life.
The plot of the "Firefall" episode ofKolchak: The Night Stalker (originally aired 8 November 1974) revolves around the spirit of a deceased arsonist that becomes the doppelgänger of a renowned orchestra conductor. He starts killing off people close to the conductor (byspontaneous human combustion), with the ultimate goal of taking over the conductor's body.
TheHammer House of Horror episode "The Two Faces of Evil" (originally aired 29 November 1980), focuses on the part of the doppelgänger mythology where meeting yours is a harbinger of your imminent death.
In the season two finale ofTwin Peaks—"Beyond Life and Death" (originally aired 10 June 1991)—Special AgentDale Cooper encounters a variety of doppelgängers in the Black Lodge, one of whom is a malevolent version of himself. Cooper's doppelgänger switches places with him at the conclusion of the episode, trapping the original in the Black Lodge. A total of three different doppelgängers are dispatched from the mysterious Black Lodge to bedevil the forces of good in Showtime's 2017 seriesTwin Peaks: The Return.
InBuffy the Vampire Slayer's season three episode "Doppelgangland" (originally aired 23 February 1999), Willow encounters her vampire double who was first introduced seven episodes previously (in "The Wish", originally aired 8 December 1998). In the fifth-season episode "The Replacement" (10 October 2000), Xander discovers his own doppelgänger (portrayed by the actor's identical twin brother).
InHow I Met Your Mother, all five main characters have run-ins with their doppelgängers at certain points. Ted, whose doppelgänger is a luchador, Marshall, whose doppelgänger has a mustache, Robin, whose doppelgänger is a lesbian, Lily, whose doppelgänger is a stripper connected to Russian gangsters, and Barney, whose doppelgänger is a doctor.
In the 2010s CW supernatural drama series,The Vampire Diaries, actressNina Dobrev portrayed the roles of several doppelgängers; Amara (the first doppelgänger), Tatia (the second), Katerina Petrova/Katherine Pierce (the third) and Elena Gilbert (the fourth). The series mainly focused on the doppelgängers of the sweet & genuine Elena and the malevolent Katherine. In the same series,Paul Wesley portrays Stefan Salvatore and his doppelgängers Tom Avery and Silas.
Starting with thesecond season ofThe Flash, doppelgängers play a key role in the development of the series. Doubles from variousEarths in themultiverse are defined as such. The person with multiple counterparts who appeared in the series wasHarrison Wells.
In the Italian supernatural drama television seriesCuron (aired 2020), the lake of the titular town spawns murderous doppelgängers.
The 1987Nintendo gameZelda II: The Adventure of Link features an enemy known as Dark Link, also known as Shadow Link, who serves as the final boss of the game. Dark Link has since made appearances as boss characters in the following titles, and as a cameo appearance in theSuper Smash Bros. series.
The 1995Ubisoft platforming video gameRayman, features and enemy during the final level in Candy Château, the main antagonist Mr Dark creates Bad Rayman using magic, an evil shadow "doppelgänger" of Rayman who copies every single move Rayman makes and if he touches Bad Rayman he will instantly die.
The 1995 video gameAlone in the Dark 3 features a nameless enemy that Edward Carnby calls "his double", a doppelgänger that mirrors the protagonist's moves to stop him from climbing the Water Tank. He is fused to Carnby after they touch hands.
The 1997Konami gameCastlevania: Symphony of the Night features an enemy boss known simply as "Doppelganger", a duplicate of the main protagonistAlucard. The enemy mimics the movement and attack patterns of the player.
The 1998 computer role playing gameBaldur's Gate employs doppelgängers as a plot device, and as a type of enemy monster that antagonizes the player's party of characters, as do both of the games major sequels. The game series usesDungeons and Dragons mechanics, in which the existence of doppelgängers as evil magical creatures is a feature.
In the 1999 gameFinal Fantasy VIII, SeeD mercenaries andForest Owls resistance fighters devise a complicated plan to kidnap the president of GalbadiaVinzer Deling, which includes switching the presidential train wagon from its tracks and replacing it with a mockup. Deling foresees the plan and sends ashapeshifter monster to take his place, who attacks the game protagonists. The monster is ultimately killed, but the plan's failure forces the Forest Owls into hiding.
The 2002 MMORPGRagnarok Online features a boss-type monster named "Doppelganger", a demon who summons Nightmares that looks like a shadow of the default appearance for the male Swordsman class.
The 2005Capcom gameDevil May Cry 3: Dante's Awakening also features an enemy boss known as "Doppelganger" that is fought near the end of the game. ResemblingDante's Devil Trigger form, it also mimics several of Dante's moves. Upon defeating the demon boss, Dante acquires a style "referred to as the Doppelganger style" that allows him to create a shadow copy of himself to assist him in battle in exchange for consuming Dante's Devil Trigger Gauge.
The 2007 videogameSuper Mario Galaxy features a doppelgänger named Cosmic Mario, where he appears in Honeyhive Galaxy, Freezeflame Galaxy, Gold Leaf Galaxy, and Sea Side Galaxy under the effect of the Cosmic Clone comet effect, and challenges Mario to a race.
The 2010 video gameAlan Wake and its 2012 sequelAlan Wake's American Nightmare feature the character of Mr. Scratch, a doppelgänger of protagonist Alan Wake created as a supernatural manifestation of negative rumors spread about the character after his disappearance at the end of the first game, and who seeks to take over and ruin Wake's life.
The 2015Konami gameMetal Gear Solid V: The Phantom Pain plot revolves around the story ofPunished "Venom" Snake who has been chosen as a decoy to replicate and take on the persona of the legendary soldierBig Boss. He is referred to as Big Boss's Doppelgänger going forward. Venom Snake was originally a Combat Medic who worked closely with Big Boss and even dived in front of Big Boss during an explosion to save him leaving the medic with helicopter shrapnel stuck in the appearance of a horn in his forehead. Following the explosion whilst in a comatose state, the medic is unknowingly selected to be physically altered via plastic surgery to become Big Boss's Doppelgänger/Stand-in and also brainwashed to believe himself to actually be Big Boss.
The 2016 gameDishonored 2 features a character, Duke Luca Abele of Serkonos, who in the second-last mission of the game is revealed to have employed a "body double" as protection. Players must make a choice to either eliminate the Duke or work with his body double for a non-lethal approach to the mission.
The Alternates, the main antagonistic force in theanalog horror web seriesThe Mandela Catalogue, are a race of demons that are marked by their ability to almost perfectly replicate human beings.
Criminologists find a practical application in the concepts of facial familiarity and similarity due to the instances of wrongful convictions based oneyewitness testimony. In one case, a person spent 17 years behind bars persistently denying any involvement with the crime of which he was accused. He was finally released after someone was found who shared a striking resemblance and the same first name.[41]
In 1914, Otto Rank began to study the concept of the Doppelgänger and its potential in psychoanalysis.[42] Later, in 1919, Sigmund Freud would expand on the psychoanalytical value of Doppelgängers in his workThe Uncanny. Freud explains that the Doppelgänger, or 'the double,' is an idea rooted in the narcissism of children and is found in mirrors, guardian spirits, souls, and the thoughts of terror associated with death. The double begins as a comforting symbol of immortality, but it soon ends as a bringer of death.[43] The Doppelgänger is also a manifestation of repressed thoughts related to the psychoanalytical concept of negation. The negation involved with the appearance of the Doppelgänger is used as a tool to map out an individual's ego.[44]
^Fleming, Paul (2006).The Pleasures of Abandonment: Jean Paul and the Life of Humor. Königshausen & Neumann. p. 126, footnote 13.ISBN978-3-8260-3247-9.In one of the stranger twists of fate in literary history, Jean Paul coins two terms inSiebenkäs, "Doppelgänger" and "Doppeltgänger". The term Jean Paul uses to describe Siebenkäs and Leibgeber is "Doppeltgänger", which he defines in a footnote: "So heißen Leute, die sich selber sehen" ["the name for people who see themselves"] (2, 67). Earlier inSiebenkäs theneologism "Doppelgänger" also appears for the first time and means something quite different. In a description of the wedding banquet in the first chapter, the food is so delicious and abundant that "not only was one course [Gang] served but also a second, aDoppelgänger" [nicht bloß ein Gang aufgetragen wurde, sondern ein zweiter, ein Doppelgänger] (2, 42). "Gang" in German has multiple meanings, ranging from a "walk" to the "course" of a meal; according to Jean Paul, when people "see themselves", when one "goes twice", one is aDoppeltgänger; when one has a meal of two courses, in which the second doesn't come second but together with the first, this is aDoppelgänger.
^Leonard Zusne, Warren H. Jones (1989).Anomalistic Psychology: A Study of Magical Thinking. Lawrence Erlbaum Associates. p. 121.ISBN978-0-805-80507-9.
^Ganander, Christfrid. Mythologia fennica; eller, Förklaring öfver de nomina propria deastrorum, idolorum, locorum, virorum, & c .. Abo, Tryckt i Frenckellska boktryckeriet, 1789.
^Webb, Stuart. Ghosts. New York, Rosen Pub., 2013.
^Bane, Theresa. Encyclopedia of spirits and ghosts in world mythology. Jefferson, NC, McFarland & Company, Inc., Publishers, 2016; see also Christfrid Ganander'sMythologia Fennica
^Mistica ebraica. Testi della tradizione segreta del giudaismo dal III al XVIII secolo Giulio Einaudi - Torino, 1995ISBN88-06-13712-3
^Blackman, Winifred.The Fellahin of Upper Egypt. pp. 69–71.
^The Autobiography of Wolfgang von Goethe. Translated by John Oxenford. Horizon Press, 1969. This example cited by Crowe inThe Night-Side of Nature (1848).
^Damas Mora JM, Jenner FA, Eacott SE (1980). "On heautoscopy or the phenomenon of the double: Case presentation and review of the literature".Br J Med Psychol.53 (1):75–83.doi:10.1111/j.2044-8341.1980.tb02871.x.PMID6989391.
^Brugger, P; Agosti, R; Regard, M; Wieser, H. G; Landis, T (1994). "Heautoscopy, epilepsy, and suicide". Journal of Neurology, Neurosurgergy and Psychiatry 57: 838–839.
Brugger, P; Regard, M; Landis, T. (1996).Unilaterally Felt "Presences": The Neuropsychiatry of One's Invisible Doppelgänger. Neuropsychiatry, Neuropsychology, and Behavioral Neurology 9: 114–122.
Keppler, C. F. (1972).The Literature of the Second Self. University of Arizona Press.
Maack, L. H; Mullen, P. E. (1983).The Doppelgänger, Disintegration and Death: A Case Report.Psychological Medicine 13: 651–654.
Miller, K. (1985).Doubles: Studies in Literary History. Oxford University Press.
Rank, O. (1971, originally published in German, Der Doppelgänger, 1914).The Double: A Psychoanalytic Study.The University of North Carolina Press.
Prel, Carl du,Die monistische Seelenlehre, Beitrag zur Lösung des Menschenrätsels, Leipzig, Günthers Verlag, 1888.
Reed, G. F. (1987).Doppelgänger. In R. L. Gregory,The Oxford Companion to the Mind. Oxford University Press. pp. 200–201.
Todd, J; Dewhurst, K. (1962).The Significance of the Doppelgänger (Hallucinatory Double) in Folklore and Neuropsychiatry. Practitioner 188: 377–382.
Todd, J; Dewhurst, K. (1955).The Double: Its Psycho-Pathology and Psycho-Physiology. Journal of Nervous and Mental Disease 122: 47–55.
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