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We report results from^ 135,137 Ba NMR spectroscopy and relaxation rate (1/T 1) measurements in single crystal Ba 3 Mn 2 O 8, an S= 1 dimer system with a singlet ground state. Thermodynamic measurements have shown it has multiple field-induced phase transitions for fields exceeding a critical field H c1∼ 90 kOe and varying with field orientation. We have evaluated the hyperfine couplings and electric field gradients in the normal phase for one of the two inequivalent Ba sites, and find a significant anisotropic component to the hyperfine coupling. Measurements of 1/T 1 made at fixed fields down to temperatures T< 0.4 K are consistent with critical behavior in the vicinity of H c1. However, lower temperatures are needed to clarify the universality class. Goals for upcoming experiments include a determination of the spectrum in the low-symmetry phases and an evaluation of 1/T 1 for T< 0.4 K. This work is …