Many main-sequence stars are surrounded by dusty debris disks, continually replenished by colliding asteroids and comets in orbit around the stars. Studying the location, mass and morphology of these disks provides crucial information about the outcome of planet formation in these systems and is revolutionising our understanding of the planet formation processes. For the 10 or so disks which have been resolved, observed structures have been used to pinpoint the location of unseen planets; many more have had their disks characterised by their spectral energy distributions, showing that these disks are the extrasolar equivalents of the Kuiper and asteroid belts in the Solar System
