Composer–performer: someone who both writes and plays. There is nothing remarkable about the composer–performer in the jazz world; most of the great jazz composers were also its best instrumental practitioners. This is rare in the history of Western classical music though, as the composer has most often remained hidden, separate from the musicians who performed their works. In this talk, Anna Webber argues that jazz’s composer–performers thus occupy a unique and privileged position: they may create the ideal vessels for their own improvisation, composing shapes that most perfectly incorporate their priorities and desires as performers.