Although the sympathetic depiction of Otherness in The Travels of Sir John Mandeville is acknowledged to be indicative of the writer's celebrated tolerance, few critics have ventured to explore how Mandeville creates it. Yet his presentation of the Other is as much a product of his cultural openness as it is the result of a conscious process of careful psychological negotiation of difference in which the text engages with the reader via the medium of the Mandeville persona. The Other is imagined so convincingly by this fourteenth-century writer that he endows it with a complex existence of its own which transcends what Ian Macleod Higgins calls a 'self-critical mirror'. Foucault's notion of 'transgression' proves instrumental in elucidating the way in which Mandeville erects his image of the Other and then, by employing a number of examples, how the text and the language of The Travels convey this 'transgression'. The second aprt of the article evaluates Mandeville's categories of perception by comparing them with the cognitive paradigms expressed by his sources and some of his contemporaries.