Berio wrote "Sequenza III" for a virtuoso singing actress - such as Cathy Berberian, his wife and the work's dedicatee. Singing is only one of the many expressive modes the human voice has, and Berio makes use of a number of them. His explanation of the symbols used in the score lists 15 techniques, among them "salvoes of laughter," "teeth-chattering," "tongue-trill against the upper lip," as well as 44 agogic markings such as "far away," "dreamy," "ecstatic," "extremely intense" and "fading away."

Thus "Sequenza III" is a unique challenge, an incomparable piece of musical theatre for a singer.