The disparagement of multilingualism is a European development of the 18th and 19th centuries in which one national language and national literature were advocated, established and institutionalised. Multilingual writers made use of the creative potential of several languages even then. However, they often adapted to an increasingly monolingual book market, which made their individual multilingualism invisible. This is evident in literary historiography which established a monolingual national canon. Researching hidden multilingualism is often difficult: since multilingual texts by multilingual writers were often not published or were published in a monolingual version, sources are scarce. Literary histories of the time often do not mention multilingualism. Furthermore, many multilingual writers were members of minority groups (women, Jewish, Non-European) and thus often neglected. The volume offers methods and theories to systematically approach this hidden material, as well as case studies on authors and national literatures in a multilingual context. It thus contributes to the restructuring of a multilingual transnational literary history that is applicable to different philologies.