  The electron magnetic moment,$-\mu/\mu_B = g/2 = 1.001 \, 159 \, 652 \, 180
\, 59 \, (13) \, [0.13\, \rm{ppt}]$, is determined 2.2 times more accurately
than the value that stood for 14 years. The most precisely determined property
of an elementary particle tests the most precise prediction of the Standard
Model (SM) to $1$ part in $10^{12}$. The test would improve an order of
magnitude if the uncertainty from discrepant measurements of the fine structure
constant $\alpha$ is eliminated since the SM prediction is a function of
$\alpha$. The new measurement and SM theory together predict
$\alpha^{-1}=137.035 \, 999 \, 166 \, (15) \, [0.11 \, \rm{ppb}]$ with an
uncertainty ten times smaller than the current disagreement between measured
$\alpha$ values.
