Abba Swedish pop group. They became famous with their winning song in the 1974 Eurovision Song Contest, ‘Waterloo’. During the 1970s, they were the world’s most successful pop group, selling huge numbers of records. Their style was based on the use of multitracked vocals, set against backing tracks drawing on dance music of the time.

Abbado, Claudio (b. 1933) Italian conductor. He studied conducting in Milan and Vienna, becoming the music director at La Scala, Milan, in 1971, where he included 20th-century works in the company’s repertory. He became principal conductor of the London Symphony Orchestra in 1979, and succeeded Karajan as chief conductor of the Berlin Philharmonic in 1990. Abbado’s recordings encompass a wide range of music, including the symphonies of Beethoven, Brahms, and Mahler, and many operatic works.

Adams, John (b. 1947) American composer and conductor. He studied at Harvard with Kirchner and Sessions. His early pieces such as Phrygian Gates (1977) and Shaker Loops (1978) drew on the minimalist style of Reich and Glass. The large-scale pieces of the next decade, such as Harmonium (1981) and Harmonielehre (1985), extended these techniques with a command of large orchestral forces and a nod to the late-Romantic tradition. Adams’s operas Nixon in China (1987) and The Death of Klinghoffer (1991) drew on contemporary political events. Significant works of the 1990s included the Violin Concerto (1993) and El NiɁo (2000). Adams was also particularly active as a conductor during the 1990s, appearing with prominent American and European orchestras.

Ade, ‘King’ Sunny (b. 1946) Nigerian performer, known as the ‘King’ of Juju music. After achieving huge popularity in his home country, he was promoted in Europe by Island Records during the 1980s. Ade’s bands usually include multiple guitarists and drummers.