In most genres of fiction women dressed as men (and vice versa, though much less common) are frequently found. In the 18th and 19th centuries, such disguises flourish in innumerable Gothic tales, and in the "Mysteries" tales which urbanized the Gothic and were made famous by writers like Eugène Sue, Alexandre Dumas and Charles Dickens. In the 20th century, they show up in detective novels – quite often, for instance, in the Brother Cadfael mysteries by Ellis Peters (Edith Pargeter), which are set in what is almost a Land-of-Fable 12th-century England – and in various kinds of thriller. The example of Sue and further fabulators of the Mysteries of Paris and other Cities points to the usefulness of GD as a plot device in the costume drama of urban life; but the example of the Brother Cadfael stories demonstrates more universal points: the threatening allure of the impostor; the subversive consequences of the need of women to act as protagonists in their own stories; the arousal of discovery.
In fantasy, straightforward GD is less common than it could be, for the very good reason that the conventions of fantasy permit much more profound means of concealment. The travelling warrior in Peter S Beagle's The Innkeeper's Song (1993) does not disguise himself as a woman: he shapeshifts (> Shapeshifters) into one. Cara, in Geoff Ryman's The Warrior who Carried Life (1985) magically transforms herself into a man to become strong and nasty enough to avenge the torment and mutilation of her family and herself. The threatening Trompe-L'oeil indeterminacy generated by this figure derives not from clothing but from essence: what it loses as commentary on role typing it gains through its obedience to the fundamental metamorphosing structure of fantasy texts. Nor is Ozma of Oz disguised as Tip in The Marvelous Land of Oz (1904): she is Tip until the time comes for him to be transformed back into a princess (> Hidden Monarch). In Dead Again (1991) the two main protagonists are gender-reversed Reincarnations of their earlier selves.
But GDs do appear, especially in Sword-and-Sorcery tales, where the disguise helps create narrative suspense. There is, of course, precedent in Mythology and Legend: Achilles famously "hid himself among women", and Thor had to disguise himself as Freya as a ruse to recover his stolen hammer. In the joyful melodramatic excesses of Joan Aiken's James III sequence, set in an Alternate-World England, the discovery that Cris – in The Cuckoo Tree (1971) – is actually a girl seems no more than part of the general texture, but there are more profound examples. In J R R Tolkien's The Lord of the Rings (1954-1955) Éowyn joins the army of Rohan in disguise as Dernhelm. In John Myers Myers's Silverlock (1949) Rosalette goes incognito as the male Nicolind partly for safety in the wild and partly to check out her boyfriend Aucando. The young protagonist of Rhoda Lerman's The Book of the Night (1984) arrives on Iona disguised as a boy. In the movie Dragonslayer (1981), a girl dresses as a male in order to escape the annual lottery among virgins (> Virginity) to determine the year's sacrifice to a Dragon; and in The Book of Joanna: A Fantasy Based on Historical Legend (1947) by George Borodin (real name George Milkomane; 1903-1996), a woman disguised as a man makes her way in the world, eventually becoming Pope, which is upsetting to the Angels in Heaven. Any fantasy involving Pope Joan is obviously rooted in GD. Patience, the protagonist of Orson Scott Card's Science Fantasy Wyrms (1987), spends much of her time disguised as a male: she is, after all, the rightful king of her land. The protagonist of Lucy Cullyford Babbitt's Melde sequence likewise deems it sensible to go dressed as a boy. In François de Salignac de la Mothe Fénelon's Les aventures de Télémaque (1699; trans as The Adventures of Telemachus 1699 UK) the goddess Minerva disguises herself as a male to accompany and advise the protagonist. The character Alyss, who appears in many of John Grant's novels, is frequently mistaken for a boy, and does not always disabuse people of their error. The occasional trope of a male hero nurturing strange lusts for a pretty young male Companion – before discovering that this love may dare speak its name – can be exemplified by Alexander de Comeau's Monk's Magic (1931).
Men disguised as women are less common, and are often treated humorously, as with Toad-as-Washerwoman in Kenneth Grahame's The Wind in the Willows (1908), the ghostly King Smoit of James Branch Cabell's Jurgen: A Comedy of Justice (1919) – who recalls "climbing out of gaol windows figged out as a lady abbess" – and Madmartigan, in Willow (1988), who seems habitually to disguise himself as female in order to dodge the wrathful husbands of his adulterous lovers. In The Devil-Doll (1936), however, there is no humorous intent in Lavond's disguise as Mme Mandelip. Although not fantasies, both Tootsie (1982) and Mrs Doubtfire (1993) are fantastications whose plot centres on transvestite men. In Arabian Fantasy, of course, there are various examples of men adopting female guise in order to inveigle themselves into harems. And in the UK version of Elizabeth Hand's Waking the Moon (1994 UK), one young man, sexually victimized by the Goddess, lives subsequently for many years as a woman.