  Domain wall fermions are a new lattice fermion formulation which preserves
the full chiral symmetry of the continuum at finite lattice spacing, up to
terms exponentially small in an extra parameter. We discuss the main features
of the formulation and its application to study of QCD with two light fermions
of equal mass. We also present numerical studies of the two flavor QCD
thermodynamics with aT = 1/4.
