When a violinist lamented on the dearth of violin duets, Berio instantly began the process of creating a series of short duos, each named in honor of a friend or fellow musician/composer. Over the years, this set of 34 Duetti took shape, spanning a range of skill levels. Many feature a simpler role for one player, usually with an emphasis on a particular skill or technique. In her excellent transcription for two violas, Mayer-Lindenberg points out that No. 20 uses playing techniques necessary for those preparing Berio's Sequenza VI for Viola Solo. Violists have long created their own arrangements of the original violin duos. Mayer-Lindenberg has now transcribed the complete set, retaining original keys where possible or transcribing down to accommodate the viola's range.