Written between 1958 and 1995, the Sequenzas are a kind of encyclopedia of 20th Century instrumental writing; Berio uses every kind of extended technique imaginable to produce a wide range of colors and textures. He obviously knows these instruments inside and out, writing works of great complexity and intricacy that also remain natural to their respective instruments. This does not mean that he does not challenge the prevailing notion of what is "natural." In his notes for the Sequenza II for Harp, Berio complains that "French 'impressionism' has left us with a rather limited vision of the harp, as if its most obvious characteristic were that of lending itself to the attentions of loosely robed girls with long blonde tresses, capable of drawing from it nothing more than seductive glissandi. But the harp also has another harder, stronger, more aggresive face." It must be said that Berio tends to illuminate the "aggresive face" of many of the instruments. The Sequenzas for violin and viola in particular dispell the notion that the most natural thing for them is to imitate the voice. Berio has a more unique vision of the instruments' capabilities.
The Ensemble InterContemporain is the creme de la creme of modern music groups. Listening to Christopher Desjardins shred in the Sequenza VI for Viola is particularly satisfying. He plays with as much passion as he does skill, bringing out the jarring shifts in mood suggested by the Edoardo Sanguinetti verse that accomanpanies the work: "my capricious fury was once your livid calm / my song will be your very slow silence." His is of course only one of many virtuoso performances in the set. The discs on the whole make a strong case for the composer, and, more generally, for the cause of modern music.