  Our recent series of measurements at Brookhaven National Laboratory
determined the muon anomalous magnetic moment \amu to a precision of 0.5 ppm.
The final result--representing the average of five running periods using both
positive and negative muons--is $\amu ^\pm = 11 659 208(6) \times 10^{-10}$. It
lies 2.7 standard deviations above the standard model expectation, which is
based on updates given at this Workshop. Importantly, only the $e^{+}e^{-}$
annihilation and new KLOE radiative return data are used for the hadronic
vacuum polarization input. Because the systematic limit has not been reached in
the experiment, a new effort has been proposed and approved with the highest
scientific priority at Brookhaven. The goal is an experimental uncertainty of
0.2 ppm, a 2.5-fold reduction in the overall experimental uncertainty. To do so
will require a suite of upgrades and several qualitative changes in the
philosophy of how the measurement is carried out. I discuss the old and new
experiments with a particular emphasis on the technical matters that require
change for the future.
