  In quenched QED we construct a non-perturbative fermion-boson vertex that
ensures the fermion propagator satisfies the Ward-Takahashi identity, is
multiplicatively renormalizable, agrees with perturbation theory for weak
couplings and has a critical coupling for dynamical mass generation that is
strictly gauge independent. This is in marked contrast to the rainbow
approximation in which the critical coupling changes by 50% just between the
Landau and Feynman gauges. The use of such a vertex should lead to a more
believable study of mass generation.
