  We are doubtlessly familiar with some edition of Jackson's tome on
electrodynamics, and Schwinger's calculation of the anomalous magnetic moment
of the electron in QED. From the perspective of strong interactions, however,
electromagnetic effects usually amount to negligible contributions. Despite
this fact, electromagnetic probes have always been a fundamental source for our
knowledge of QCD experimentally. Elastic scattering of electrons off nucleons
provides us a window to their distributions of charge and magnetism. To account
for the spectrum of QCD at the percent level, moreover, we need isospin
breaking introduced from both quark masses and electric charges. This overview
concerns some of the prospects and progress of studying electromagnetic effects
in QCD. Our focus is divided between classical and quantum effects. In
classical electromagnetic fields, the dynamical response of QCD to external
conditions can be investigated. The vacuum and hadrons alike should be viewed
as media which respond to external fields: both magnetize and polarize in
magnetic fields, for example. At the quantum level, electromagnetism and QCD
renormalize each other. In the era of high precision lattice computations, both
strong and electromagnetic contributions must be accounted for to make
predictions at the percent level.
