  One of the greatest challenges within the Standard Model is to discover the
source of visible mass. Indeed, this is the focus of a "Millennium Problem",
posed by the Clay Mathematics Institute. The answer is hidden within quantum
chromodynamics (QCD); and it is probable that revealing the origin of mass will
also explain the nature of confinement. In connection with these issues, this
perspective describes insights that have recently been drawn using contemporary
methods for solving the continuum bound-state problem in relativistic quantum
field theory and how they have been informed and enabled by modern experiments
on nucleon-resonance electroproduction.
