Physics with a Millimole of Muons

The eventual prospect of muon colliders reaching several TeV encourages us to consider the experimental opportunities presented by very copious stores of muons, approaching $10^{21}$ per year. I summarize and comment upon some highlights of the Fermilab Workshop on Physics at the First Muon Collider and at the Front End of a Muon Collider. Topics include various varieties of $\mu\mu$ colliders, $\mu p$ colliders, and applications of the intense neutrino beams that can be generated in muon storage rings.