  The MiniBooNE neutrino detector was designed and built to look for
muon-neutrino to electron-neutrino oscillations in the mixing parameter space
region where the LSND experiment reported a signal. The MiniBooNE experiment
used a beam energy and baseline that were an order of magnitude larger than
those of LSND so that the backgrounds and systematic errors would be completely
different. This paper provides a detailed description of the design, function,
and performance of the MiniBooNE detector.
