Oliver Knussen was a British composer and conductor. Though Knussen began composing at about the age of six,; an ITV programme about his father's work with the London Symphony Orchestra prompted the commissioning for his first symphony (1966–1967). Aged 15, Knussen stepped in to conduct his symphony's première at the Royal Festival Hall, London, on 7 April 1968, after István Kertész fell ill. After his debut, Daniel Barenboim asked him to conduct the work's first two movements in New York a week later. In this work and his Concerto for Orchestra (1968–1970), he had quickly and fluently absorbed the influences of modernist composers Britten and Berg as well as many mid-century (largely American) symphonists, while displaying an unusual flair for pacing and orchestration. It was as early as the Second Symphony (1970–1971), in the words of Julian Anderson, that "Knussen's compositional personality abruptly appeared, fully formed". He was awarded CBE in the 1994 Birthday Honours.
Knussen was principal guest conductor of The Hague's Het Residentie Orkest (Residentie Orchestra) between 1992 and 1996, the Aldeburgh Festival's co-artistic director between 1983 and 1998 and the London Sinfonietta's music director between 1998 and 2002 – and became that ensemble's conductor laureate.
In 2005 Knussen was the music director of the Ojai Music Festival.
From September 2006, Knussen was artist-in-association to the Birmingham Contemporary Music Group, and from 2009 to the BBC Symphony Orchestra.
His major works from the 1980s were his two children's operas, Where the Wild Things Are and Higglety Pigglety Pop!, both libretti by Maurice Sendak.