When I first heard Luciano Berio's Duetti per due violini (1979-1983; UE 17 757), I thought how great it would be to be able to play these pieces on the viola, or to listen to them being played on violas. So I am delighted that we now have this edition for two violas and hope that many musicians and their listeners will enjoy it and get to know Berio's music even better. The Duetti nos. 1, 7, 12, 22, 26, 27, 28 and 29 were left as in the original. All the other pieces in this edition were transposed down a fifth, apart from no. 31, which was transposed down by a minor seventh, in order to maintain the original idea. The Duetti nos. 6 and 33 are not included because their character seemed to me to be too specific to the violin (e.g. through the frequent use of the open E string and the playing techniques used), meaning that a transposition and the viola sound would change their original quality too much. Although the same could be said of no. 20, we have included it in this edition because it features some of the playing techniques that we need for Berio's Sequenza VI per viola sola (1967; UE 13 726). I believe that the opportunity to prepare and practise for a large solo work by the same composer is very important and helpful, even if including it in this edition is not, from a purely musical perspective, entirely justified. Annegret Mayer-Lindenberg