This comparative study examines the prose writings of the best-known cosmopolitan authors of the Third French Republic: the modernists Jean Giraudoux, Valery Larbaud and Paul Morand, and the best-selling popular writer Maurice Dekobra. It investigates what constituted the 'cosmopolitanism' that they publicly proclaimed between the World Wars, a classification which has been widely accepted by commentators ever since. In particular, it considers whether conventional definitions of cosmopolitanism - as an unproblematic attitude of xenophilia coupled with wanderlust, or as an ecumenical humanism - can co-exist with the blind spots and prejudices of its practitioners. This book offers a comprehensive reinterpretation of the writers' identity politics based on their approach to Otherness (gender, race, nationality, political affiliation) as well as to formal innovation. It argues that cosmopolitanism is the organizing principle for their literary and existential attempts at cultivating authentic Selfhood. Through its socio-political embeddedness, this cosmopolitanism reveals the ideological and cultural preoccupations of the day.