  During the last year, analytic expressions for the two-loop QCD corrections
to the form factors for the vector, axial-vector, scalar and pseudo-scalar
vertices involving a pair of heavy quarks, $Q \bar{Q}$, were calculated. The
results are valid for arbitrary momentum transfer and mass of the heavy quarks.
These form factors have a number of applications, including anomalous
couplings, the $e^{+}e^{-} \to Q \bar Q$ cross section, and the
forward-backward asymmetry of heavy quarks. Here the $Q {\bar Q}$ threshold
cross section is presented with some new second order axial vector
contributions.
