Musical set theory provides concepts for categorizing
musical objects and describing their relationships. Many of the notions were first elaborated by
Howard in connection with
tonal music, and then mostly developed in connection with
atonal music by theorists such as
Allen , drawing on the work in
twelve-tone theory of
Milton Babbitt. The concepts of set theory are very general and can be applied to tonal and atonal styles in any
equally tempered tuning system, and to some extent more generally than that.