SCUBA, the Submillimetre Common-User Bolometer Array, built by the Royal Observatory Edinburgh for the James Clerk Maxwell Telescope, is the most versatile and powerful of a new generation of submillimetre cameras. It combines a sensitive dual-waveband imaging array with a three-band photometer, and is sky-background limited by the emission from the Mauna Kea atmosphere at all observing wavelengths from 350 microns to 2 mm. The increased sensitivity and array size mean that SCUBA maps close to 10,000 times faster than its single-pixel predecessor (UKT14). SCUBA is a facility instrument, open to the world community of users, and is provided with a high level of user support. We give an overview of the instrument, describe the observing modes and user interface, performance figures on the telescope, and present a sample of the exciting new results that have revolutionised submillimetre astronomy.