  We describe the design and performance of the Solar Tower Atmospheric
Cherenkov Effect Experiment (STACEE) in its complete configuration. STACEE uses
the heliostats of a solar energy research facility to collect and focus the
Cherenkov photons produced in gamma-ray induced air showers. The light is
concentrated onto an array of photomultiplier tubes located near the top of a
tower. The large Cherenkov photon collection area of STACEE results in a
gamma-ray energy threshold below that of previous ground-based detectors.
STACEE is being used to observe pulsars, supernova remnants, active galactic
nuclei, and gamma-ray bursts.
