This fourth volume of J P E Hartmann og hans kreds. En komponistfamilies breve 1780-1900 (J.P.E. Hartmann and his Circle. The Correspondence of a Composer Family 1780-1900) contains hitherto unknown letters which have been privately owned until now. The particular focus is on J P E Hartmann's son Emil Hartmann and his struggle for recognition as a composer and not because of his relatives. The letters elucidate this struggle and provide a wealth of information on both the everyday life and the musical scene in the second half of the 19th century in which Emil Hartmann travelled a great deal in Germany where he was a well-known figure. Thus, letters from German celebrities, such as Richard Strauss and Max Bruch are included.