Simpson composed 15 numbered string quartets; a quartet preceding this sequence was written as part of his course at Durham University and still exists there. He regarded Quartets Nos. 1–3 as forming a natural sequence, and Nos. 4–6 are a clearly distinct group related to three Beethoven quartets, though they can all be performed as entirely independent compositions. The second movement of No. 8 has the label "Eretmapodites gilletti", and the quartet is dedicated to two people including the discoverer of the mosquito with that scientific name; the ninth quartet, from 1982, is a one-movement (but subdivided, with slow and scherzando sections) palindromic 32 Variations and Fugue on a Theme by Haydn; Number 10 is entitled "For Peace". (See the article by Malcolm MacDonald in the External Links.)