Particle physics opportunities at mu(+)mu(-) colliders

We discuss the capabilities of future muon colliders to resolve important particle physics questions. A collider with c.m. energy root s = 100 to 500 GeV offers the unique opportunity to produce Higgs bosons in the s-channel and thereby measure the Higgs masses, total widths and several partial widths to high precision. At this same machine, <t(t)over bar> and W+W- threshold studies would yield superior precision in the determination of m(t) and m(w). A multi-TeV mu(+)mu(-) collider would open up the realm of physics above the 1 TeV scale, allowing, for example, copious production of supersymmetric particles up to the highest anticipated masses or a detailed study of the strongly-interacting scenario of electroweak symmetry breaking.