  In a Hamiltonian formalism we study chiral symmetry for lattice Fermions
formulated in terms of Shockley surface states bound to a wall in an extra
spatial dimension. For hadronic physics this provides a natural scheme for
taking quark masses to zero without requiring a precise tuning of parameters.
We illustrate the chiral anomaly as a flow of states in this extra dimension.
We discuss two alternatives for extending the picture to a chiral coupling of
gauge fields to such Fermions; one with a small explicit breaking of gauge
symmetry and one one with heavy mirror Fermions.
