This article discusses the use of extended techniques by Luciano Berio (1925–2003), focusing on his Sequenza XIV, for cello, finished in 2002. Our analysis attempts to demonstrate how Berio uses new ways of playing the instrument to create a kind of polyphony. The article references a large number of writings by Berio himself, including sketches, drafts and early manuscripts of Sequenza XIV, including exchanges between the composer and Rohan de Saram, for whom he wrote the piece.