  Domain wall fermions provide a complimentary alternative to traditional
lattice fermion approaches. By introducing an extra dimension, the amount of
chiral symmetry present in the lattice theory can be controlled in a linear
way. This results in improved chiral properties as well as robust topological
zero modes. A brief introduction on the subject and a discussion of chiral
properties and applications, such as zero and finite temperature QCD, N = 1
super Yang-Mills, and four-fermion theories, is presented.
