  We examine the physics capabilities of known flavor neutrino beams from
intense muon sources. We find that long-baseline neutrino experiments based on
such beams can provide precise measurements of neutrino oscillation mass and
mixing parameters. Furthermore, they can test whether the dominant atmospheric
neutrino oscillations are \nu_\mu --> \nu_\tau and/or \nu_\mu --> \nu_s,
determine the \nu_\mu --> \nu_e content of atmospheric neutrino oscillations,
and measure \nu_e --> \nu_\tau appearance. Depending on the oscillation
parameters, they may be able to detect Earth matter and CP violation effects
and to determine the ordering of some of the mass eigenstates.
