This dissertation examines the works created jointly by dramatists and composers for the French theatre in the interwar period. During this period, writers as different as they were prolific collaborated with composers to create a new genre out of a combination of music and theatre, which I call "music-theatre." These collaborations collectively constitute a unique genre for historical, aesthetic and genetic reasons. The study is centered on a discussion of five representative works of this genre: Histoire du soldat by Charles-Ferdinand Ramuz and Igor Stravinsky, L'Enfant et les sortilèges by Colette and Maurice Ravel, Les Mariés de la Tour Eiffel by Jean Cocteau and the Groupe des Six, Perséphone by André Gide and Stravinsky, and Le Livre de Christophe Colomb by Paul Claudel and Darius Milhaud. The focus of this study is on the dramatic innovation that resulted from these collaborations. I discuss the defining characteristics of the genre demonstrated in the play's themes, aesthetics, and treatment of character. Rejecting the tenets of realist and naturalist theatre, these dramatists sought new ways to represent the fantastic, supernatural and surreal on the stage; they experimented with dialogue, choreography and time schemes to evoke a world of emotional, spiritual or philosophical uncertainty. Writers also collaborated with composers for reasons relating to the cultural climate of the period. The presence of the Ballets Russes in France, the radical innovations in music pioneered by Stravinsky and Les Six, and the close friendships which developed between writers and composers, also contributed to the rise of the genre at this moment in history. These collaborations occupy an important place in the oeuvre of major writers, and yet histories of 20th century French theatre do not account for them. Through a discussion of these five plays, this study contributes a new perspective on the interwar theatre in France.