Nikolaus Harnoncourt places the musical dialogue between the individual voices of the orchestra and the imaginary dialogue between musician and listener at the center of his reflections on questions of music. Since he recognized this dialogue, which is groundbreaking for his own performance practice, as an essential means of expression for composers between 1600 and 1800, he has explored it extensively. In detailed analyses of the major works of Monteverdi and Bach, he demonstrates how this musical dialogue can be made comprehensible again today in certain aspects.