Clusters are especially prevalent in the realm of free jazz. Cecil Taylor has used them extensively as part of his improvisational method since the mid-1950s. Like much of his musical vocabulary, his clusters operate "on a continuum somewhere between melody and percussion." One of Taylor's primary purposes in adopting clusters was to avoid the dominance of any specific pitch. Leading free jazz composer, bandleader, and pianist Sun Ra often used them to rearrange the musical furniture, as described by scholar John F. Szwed: