  The leading order hadronic contribution to the muon g-2, $a_{\mu}^{HAD}$, is
determined entirely from theory using an approach based on Cauchy's theorem in
the complex squared energy s-plane. This is possible after fitting the
integration kernel in $a_{\mu}^{HAD}$ with a simpler function of $s$. The
integral determining $a_{\mu}^{HAD}$ in the light-quark region is then split
into a low energy and a high energy part, the latter given by perturbative QCD
(PQCD). The low energy integral involving the fit function to the integration
kernel is determined by derivatives of the vector correlator at the origin,
plus a contour integral around a circle calculable in PQCD. These derivatives
are calculated using hadronic models in the light-quark sector. A similar
procedure is used in the heavy-quark sector, except that now everything is
calculable in PQCD, thus becoming the first entirely theoretical calculation of
this contribution. Using the dual resonance model realization of Large $N_{c}$
QCD to compute the derivatives of the correlator leads to agreement with the
experimental value of $a_\mu$. Accuracy, though, is currently limited by the
model dependent calculation of derivatives of the vector correlator at the
origin. Future improvements should come from more accurate chiral perturbation
theory and/or lattice QCD information on these derivatives, allowing for this
method to be used to determine $a_{\mu}^{HAD}$ accurately entirely from theory,
independently of any hadronic model.
