In Baby in der Bar, a so-called "dance play" from 1927, for which the famous film theorist and critic Béla Balasz wrote the text, Grosz created an impressive synthesis of European art music and contemporary jazz elements. The music is tremendously lively, characterised by distinctive rhythmic accents and delightful polytonal growths, occasionally with clear ironic undertones.

The piece is about a baby abandoned in a bar, which suddenly grows and unsettles the men present, from its first attempts at crawling to seduction dances and boxing matches. Baby in the Bar, of which no recording has yet been found, lasts about 30 minutes. Wilhelm Grosz was one of the most versatile musical talents of the twenties. The Austrian from a wealthy Jewish family was also successful as a composer, conductor, pianist, musicologist and record producer in Germany (Mannheim and Berlin) and has been forgotten today like hardly any other musician of his stature. With his brilliant inventiveness, he broke the mould of conventional musical categories. An interdisciplinary music theatre project in the winter semester 1998/99 with Petra Eller (textile design), Sabine Wallach (visual media), Gesine Buhrow (choreography, dance), Fred Ritzel and Peter Vollhardt (music). Performances:
October 1998 and January 1999