  We present results for pion polarizabilities predicted using dispersion
relations from our earlier Amplitude Analysis of world data on two photon
production of meson pairs. The helicity-zero polarizabilities are rather stable
and insensitive to uncertainties in cross-channel exchanges. The need is first
to confirm the recent result on $(\alpha_1-\beta_1)$ for the charged pion by
COMPASS at CERN to an accuracy of 10\% by measuring the
$\gamma\gamma\to\pi^+\pi^-$ cross-section to an uncertainty of ~1\%. Then the
same polarizability, but for the $\pi^0$, is fixed to be
$(\alpha_1-\beta_1)_{\pi^0}=(-0.9\pm0.2)\times 10^{-4}$ fm$^{3}$. By analyzing
the correlation between uncertainties in the meson polarizability and those in
$\gamma\gamma$ cross-sections, we suggest experiments need to measure these
cross-sections between $\sqrt{s}\simeq 350$ and 600 MeV. The $\pi^0\pi^0$
cross-section then makes the $(\alpha_2-\beta_2)_{\pi^0}$ the easiest
helicity-two polarizability to determine.
