Physics from a Tau Charm Factory is presented. . T au Charm Factories proposed for future machines will provide powerful and unique facilities to study a variety of physics topics: the tau lepton, charm mesons, charmonium and the J/vdecays. These topics cover the physics of the members of the first and second quark doublets and the third lepton doublet. The number of Table. 1 Tau Charm Factory particle yields at 1 033 events produced in a running year of 5,000 hours is shown in table 1. This represents a factor 100-l 000 increase over previous data samples. A workshop held at Stanford Linear Accelerator Centerfll reviewed the physics,f21 the machinei and the detectori for such a facility. In this paper, highlights of this meeting will be e+eJJV 3.680 2m(T)+2 MeV 3.67 GeV lq” (3.77) ly ” (3.77) 4.03 GeV 4.14 GeV Particle JW w* z+z2+2DOTjo D+DDs+DsDs Ds’ Produced events 1 O’/month 5x1 08/month 4x1 O6 pairs/year 4x1 O7 pairs/year 4x1 O7 pairs/year 5x1 O7 pairs/year 1 O7 pairs/year 2x1 O7 pairs/year Invited talk presented at the meeting of the1989 International Symposium on Heavy Quark Physics at Cornell University, Ithaca, N.Y., June 13-17, 1989 *Work supported in part by the National Science Foundation and by the Department of Energy contracts DEAC03-76SF00515,DE-AC02-76ER01195,DE-AC03-81ER40050, DE-AC02-87ER40318 and DE-AMOS76SF000324 Tau Charm Factory Physics 2 c reviewed. We will begin with a short sketch of the machine issues and then briefly describe .topics in tau, charm and charmonium-J/v physics.