[1][2] He was born in High Wycombe, Buckinghamshire and attended the Royal Grammar School there.
From that school, he won a scholarship to read modern languages at Jesus College, Oxford in 1940.
From 1964 to 1976, he was professor of musicology at Columbia University, New York and during this period often wrote collaboratively with others such as music critic Alec Robertson.
In 1995, he was appointed as visiting professor at Goldsmiths College, London, the institution which now houses his extensive Monteverdi library.
Best known for his work on early baroque Italian composers, especially Claudio Monteverdi, and for his pioneering concerts and recordings with the Accademia Monteverdiana (which he founded), Stevens was appointed a Commander of the Order of the British Empire (CBE) in 1984.