  The hadronic light-by-light scattering contribution to muon $g-2$ is examined
using low energy effective theories of QCD, the Nambu-Jona-Lasinio model and
hidden local chiral symmetry, as guides. Our result is $- 36 \times 10^{-11}$
with an uncertainty of $\pm 16 \times 10^{-11}$, which includes our best
estimate of model dependence. This is within the expected measurement
uncertainty of $40\times 10^{-11}$ in the forthcoming experiment at Brookhaven
National Laboratory. Our result removes one of the main theoretical obstacles
in verifying the existence of the weak contribution to the muon $g-2$.
