  We present a theory of frustrated, two-dimensional, quantum antiferromagnets
in the vicinity of a quantum transition from a non-collinear,
magnetically-ordered ground state to a quantum-disordered phase. Using a
sigma-model for bosonic, spin-1/2, spinon fields, we obtain universal scaling
forms for a variety of observables. Our results are compared with numerical
data on the spin-1/2 triangular antiferromagnet.
