  Non-Perturbative Quantum Field Theory has played an important role in the
study of phenomena where a fermion condensate can appear under certain physical
conditions. The familiar phenomenon of electric superconductivity, the color
superconductivity of very dense quark matter, and the chiral symmetry breaking
of low energy effective chiral theories are all examples of that sort. Often
one is interested in the behavior of these systems in the presence of an
external magnetic field. In this talk I will outline the effects of an external
magnetic field on theories with either fermion-fermion or fermion-antifermion
condensates.
