This paper, originally the keynote address at a conference on notation in contemporary music held at Goldsmiths, University of London, in October 2013, examines the relationship between notation and improvisation in today's music. Starting from the position that improvisation is a method of composition, and that the two are in no way opposites, the author reflects on his dual practice as composer of often complexly notated scores and an improvising musician. The title subverts the familiar claim that it is improvisation that liberates the musician from the supposed tyranny of fixed notation, suggesting instead that notation may serve a valuable function in suggesting possible directions or points of focus in free improvisation.