Skellig is an opera with music by Tod Machover and a libretto based on the best-selling novel for young people by David Almond. It premiered in the UK in November 2008. Besides blending acoustics and electronics, natural noise, and soaring melodies, Skellig also presents several live performance breakthroughs. A non-professional teenage chorus is used throughout, blended seamlessly with high-level professionals; this chorus is guided by an interactive "sonic score" that provides auditory cues, textures to imitate, and electronic reinforcement for the entire 100-minute show. In addition, specially designed "ambisonics" were developed to allow sound to emanate from the stage and engulf the audience in all dimensions, the first time such a technique has been used in a full-scale theatrical setting.