The potential of muon colliders to address fundamental physics issues is explored, with emphasis on understanding the nature of electroweak symmetry breaking. The $s$-channel production of Higgs bosons, unique to a muon collider, along with precision measurements of W^+W^-, t\bar t, and Zh thresholds would determine the properties of Higgs bosons and test electroweak radiative corrections. At the high energy frontier, a 4 TeV muon collider is ideally suited to study either the production of supersymmetric scalar particles or a strongly interacting WW sector.

7 pages, Latex2.09, uses aip2col.sty (included) and epsf.sty. 14 postscript figures. Talk present at FCP97, Workshop on Fundamental Particles and Interactions, Vanderbilt University, May 1997. Postscript file of complete paper also available at http://pheno.physics.wisc.edu/pub/preprints/1997/madph-97-1012.ps.Z or at ftp://pheno.physics.wisc.edu/pub/preprints/1997/madph-97-1012.ps.Z