We include two loop, relativistic one loop and second order relativistic tree level corrections, plus leading nonperturbative contributions, to obtain a calculation of the lower states in the heavy quarkonium spectrum correct up to, and including, O ( α 4 s ) and leading Λ 4 / m 4 terms. This allows us, in particular, to obtain a model-independent determination of the pole masses of the b,c quarks, m b = 5015 + 110 − 70 MeV , m c = 1884 + 222 − 133 MeV , to which correspond the ¯ MS masses m b ( m 2 b ) = 4453 + 50 − 32 MeV , m c ( m 2 c ) = 1547 + 169 − 102 MeV . The decay Γ ( → Υ e + e − ) is found to be in agreement with experiment, Γ ( → Υ e + e − ) = 1.135 + 0.27 − 0.29 keV ( expt . = 1.320 ± 0.04 keV ) , and the hyperfine splitting is predicted to be M ( Υ ) − M ( η ) = 48.5 + 15.7 − 12.2 MeV .