This chapter focuses on Sonia Delaunay (1885–1979), a famous painter and fashion and costume designer who dressed such movie stars and celebrities as Gloria Swanson, Nancy Cunard, and Alma Gropius. Inspired by the 1909 costumes designed by Léon Bakst for Diaghilev and the Ballets Russes, and reacting against Art Nouveau’s excessive reliance on flowers and plants for every type of decoration, Delaunay transported modernist aesthetics onto the body through a fashion. With dresses that featured a straight neckline, little complicated seaming, and no waistline, she gave enormous importance to color, which she believed determined the rhythms of the geometrically patterned textiles that she designed.