Michael B. Tretow

Bo Michael Tretow (born 20 August 1944 in Norrköping) is a Swedish record producer and audio engineer, musician and composer, best known for his work with the Swedish pop group ABBA (1970–1982), and with the musical Chess. He has also composed several themes and jingles for Swedish national radio and television.

Tretow began working at Metronome Studios in Stockholm in 1967, and later worked at GLN (Glenmark) studios for two years before coming to ABBA's Polar Studios in 1978, where he eventually became studio manager. Tretow experimented with different recording techniques, and played an essential part in creating the "ABBA sound".