  Muon colliders and neutrino factories are attractive options for future
facilities aimed at achieving the highest lepton-antilepton collision energies
and precision measurements of parameters of the Higgs boson and the neutrino
mixing matrix. The performance and cost of these depend on how well a beam of
muons can be cooled. Recent progress in muon cooling design studies and
prototype tests nourishes the hope that such facilities can be built during the
coming decade. The status of the key technologies and their various
demonstration experiments is summarized.
