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We extend results first announced by Franz et al. (1998), that identified vA351 = H346 in the Hyades as a multiple star system containing a white dwarf.With Hubble Space Telescope Fine Guidance Sensor fringe tracking and scanning,and more recent speckle observations, all spanning 20.7 years, we establish aparallax, relative orbit, and mass fraction for two components, with a period,$P=2.70$y and total mass 2.1 Msun. With ground-based radial velocities from theMcDonald Observatory Otto Struve 2.1m telescope Sandiford Spectrograph, andCenter for Astrophysics Digital Speedometers, spanning 37 years, we find thatcomponent B consists of BC, two M dwarf stars orbiting with a very short period(P_ BC=0.749 days), having a mass ratio M_C/M_B=0.95. We confirm that the totalmass of the system can only be reconciled with the distance and componentphotometry by including a fainter, higher mass component. The quadruple systemconsists of three M dwarfs (A,B,C) and one white dwarf (D). We determineindividual M dwarf masses M_A=0.53+/-0.10 Msun, M_B=0.43+/-0.04Msun, andM_C=0.41+/-0.04Msun. The WD mass, 0.54+/-0.04Msun, comes from cooling models,an assumed Hyades age of 670My, and consistency with all previous and derivedastrometric, photometric, and RV results. Velocities from H-alpha and He Iemission lines confirm the BC period derived from absorption lines, withsimilar (He I) and higher (H-alpha) velocity amplitudes. We ascribe the largerH-alpha amplitude to emission from a region each component shadows from theother, depending on the line of sight.

Dissecting the Quadruple Binary Hyad vA 351 -- Masses for three M Dwarfs and a White Dwarf