  I review various aspects of chiral symmetry and its spontaneous breaking on
null planes, including the interesting manner in which Goldstone's theorem is
realized and the constraints that chiral symmetry imposes on the null-plane
Hamiltonians. Specializing to QCD with N massless flavors, I show that there is
an interesting limit in which the chiral constraints on the null-plane
Hamiltonians can be solved to give the spin-flavor algebra SU(2N), recovering a
result originally found by Weinberg using different methods.
