  A fundamental property of QCD is the presence of the chiral anomaly, which is
the primary component of the $\pi^0\rightarrow\gamma\gamma$ decay amplitude.
Based on this anomaly and its small ($\simeq$ 4.5%) chiral correction, a firm
prediction of the $\pi^0$ lifetime can be used as a test of QCD at confinement
scale energies. The interesting experimental and theoretical histories of the
$\pi^0$ meson are reviewed, from discovery to the present era. Experimental
results are in agreement with the theoretical prediction, within the current
($\simeq$ 3%) experimental error; however, they are not yet sufficiently
precise to test the chiral corrected result, which is a firm QCD prediction and
is known to $\simeq$ 1% uncertainty. At this level there exist experimental
inconsistencies, which require attention. Possible future work to improve the
present precision is suggested.
