  We review recent progress in the computation of leading quantum corrections
to the energies of classical solitons with topological structure, including
multi-soliton models in one space dimension and string configurations in three
space dimensions. Taking advantage of analytic continuation techniques to
efficiently organize the calculations, we show how quantum corrections affect
the stability of solitons in the Shifman-Voloshin model, stabilize charged
electroweak strings coupled to a heavy fermion doublet, and bind Nielsen-Olesen
vortices at the classical transition between type I and type II
superconductors.
