hep-ph/9506450 Isospin Breaking and the Top-Quark Mass in Models of Dynamical Electroweak Symmetry Breaking Authors: R. Sekhar Chivukula, Bogdan Dobrescu, John Terning (Boston University) Comments: 9 pages, 6 Postscript figures, uses epsf.sty, talk presented by RSC at Workshop on Top Quark Physics, Iowa State University, May 25-26, 1995 and Yukawa International Seminar `95, Kyoto, Aug. 21-25, 1995. Minor typo fixed Report-no: BUHEP-95-22 In this talk we review the physics of top-quark mass generation in models of dynamical electroweak symmetry breaking and the constraints on this physics arising from limits on the deviation of the weak interaction $\rho$-parameter from one. We then discuss top-color assisted technicolor in this context.