A writer of avant garde serious music popular musical style .
A writer of avant garde serious music is his collaborations with playwright Bertolt Brecht on projects such as The Threepenny Opera nevertheless gave an early indication of his interest in writing in an easily accessible .
A writer of avant garde serious music , his collaborations with playwright Bertolt Brecht on projects such as The Threepenny Opera nevertheless gave an early indication of his interest in writing in an easily accessible , popular musical style .