The long-term friendship between Anne-Sophie Mutter and Krzysztof Penderecki has not only produced the second violin concerto (''Metamorphoses'') and the second sonata for violin, but also the new Duo concertante per violino e contrabbasso. To be more precise, it was the Anne-Sophie Mutter Foundation for the encouragement of highly talented string players which issued the commission for this duo. The two dedicatees, Anne-Sophie Mutter and her scholarship holder Roman Patkoló, gave the first performance of this work in Hanover The challenging composition in a closed and compressed form contains a variety of different atmospheres ranging from expressive recitatives to wild scampering scherzando passages. It presents audiences with several surprises and is an effective combination of old and new. The double bass part is notated in scordatura, i.e. the strings are tuned a whole tone higher than is customary.This work provides a welcome addition to the chamber music repertoire, particularly for double bass virtuosos.