Luciano Berio is one of the most important Italian avant-garde composers of the post-war period. His varied output includes electronic music and many works for traditional instruments and voices, although often including the exploration of non-traditional playing and singing techniques. Sequenza V is one in a series of ten works for solo instruments or voice in which Berio expands the technical horizons for the performer. In Sequenza V, for example, the trombonist must explore extremes of both dynamic levels and registers and sing while exhaling or inhaling.

Sequenza V (1966) is a programmatic work based upon the character of a famous clown named Grock who was Berio's neighbor when he was a child. Berio remembers stealing oranges from the clown's yard as a young boy, but then at age eleven saw Grock perform. Grock's clowning was legendary, simultaneously tragic and comic with few spoken words. He often said "Pourquoi?" ("Why?"), which for this work Berio translates into English and breaks into three phonemes ("u," "a," "i,"), each uttered by the trombonist. The sounds are also played though the trombone with the use of a plunger mute. In the second section of the work the trombonist sits down to explore the inner life of the clown. Tragedy and comedy intermingle and the piece ends in resignation. Demands on the performer include the cessation of normal breathing for more than three minutes.