Exploiting the manipulation of the SLC electron-beam polarization, we present precise direct measurements of the parity violation parameters Ac and Ab in the Z boson–c quark and Z boson–b quark coupling. Quark/antiquark discrimination is accomplished via a unique algorithm that takes advantage of the precise SLD CCD vertex detector, employing the net charge of displaced vertices as well as the charge of kaons that emanate from those vertices. From the 1996-98 sample of 400,000 Z decays, produced with an average beam polarization of 73.4%, we find Ac = 0.673±0.029(stat.) ± 0.023(syst.) and Ab = 0.919 ± 0.018(stat.) ± 0.017(syst.).