  The hadronic light-by-light scattering contribution to muon $g-2$ is examined
based on the low energy effective theories of QCD, the Nambu-Jona-Lasinio model
and hidden local symmetry approach, supplemented by a general information
concerning the asymptotic behavior of QCD.
  Our result is $- 52 \times 10^{-11}$ with an uncertainty of $\pm 18 \times
10^{-11}$, 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 $g-2$.
