Surviving in six extant manuscripts and referenced by later English luminaries such as Geoffrey Chaucer, Sir Thomas Malory, and John Skelton, Lybeaus Desconus ranks among the most popular of Middle English romances. Dated to the mid-fourteenth century, it belongs to the widely disseminated narrative tradition of “the Fair Unknown,” in which a handsome and mysterious young outsider journeys to King Arthur’s court to prove his worth despite his illegitimate birth. Granted the opportunity to demonstrate his physical prowess and hidden nobility, Lybeaus undertakes a series of quests that pit him against supernatural foes, teach him chivalric conduct, overcome his illegitimacy, and restore his patrimony. This edition presents two manuscript versions belonging to distinct textual traditions of the tale, with the original author’s version preserved in Lambeth Palace MS 306, and the fifteenth-century revision from Naples XIII.B.29 reflecting a late medieval trend of adapting earlier material to new contexts.