This article provides an insight into the history of interactive graphicalcontrol interfaces for computer-based and computer-assisted musicapplications and identifies a number of the challenges which currentlyface contemporary designers of new software and hardware tools in thiscontext. By studying some of the key features of this rich and variedlegacy, it is possible to establish some useful criteria to underpin thedevelopment of new and improved tools for manipulating visual representationsof music data which can be as diverse as common music notation, acousticspectra, and all manner of simulations modelling the physical controlsurfaces associated with devices such as commercial synthesizers and audiomixing consoles.