  The muon anomaly $a_\mu=(g_\mu-2)/2$ showing a persisting 3 to 4 $\sigma$
deviation between the SM prediction and the experiment is one of the most
promising signals for physics beyond the SM. As is well known, the hadronic
uncertainties are limiting the accuracy of the Standard Model prediction.
Therefore a big effort is going on to improve the evaluations of hadronic
effects in order to keep up with the 4-fold improved precision expected from
the new Fermilab measurement in the near future. A novel complementary type
experiment planned at J-PARC in Japan, operating with ultra cold muons, is
expected to be able to achieve the same accuracy but with completely different
systematics. So exciting times in searching for New Physics are under way. I
discuss the role of meson physics in calculations of the hadronic part of the
muon g-2. The improvement is expected to substantiate the present deviation
$\Delta a_\mu^{\rm New \ Physics}=\Delta a_\mu^{\rm Experiment}- \Delta
a_\mu^{\rm Standard \ Model}$ to a 6 to 10 standard deviation effect, provided
hadronic uncertainties can be reduce by a factor two. This concerns the
hadronic vacuum polarization as well as the hadronic light-by-light scattering
contributions, both to a large extent determined by the low lying meson
spectrum. Better meson production data and progress in modeling meson form
factors could greatly help to improve the precision and reliability of the SM
prediction of $a_\mu$ and thereby provide more information on what is missing
in the SM.
