Abstract. Gravitation becomes unified with quantum rnechanics when we recognize that the spacetirne tetrads and the rnatter fields of Ferrnions ate the integral and half-integral spin representations of the Einstein group, E, the global extension of the Poincar› group to a curved spacetirne M. There are 8 fundamental spinor representations of the E group, interchanged by P, T, and C: the degree-one maps of spin space over M. Tensor products of 2 spinor fields build Clifford vectors or 1 forrns, e.g. the spacetime tetrads. It takes tensor products of all 8 spinor ¡ to build a natural 4 forrn; in particular, our E-invariant Lagrangian density /~g E A a (M) C | (M). We propose a simple forrn for /~g: the 8-spinor factorization of the Maurer-Cartan 4-forro, F/4. The spin connections ~~ step off the conjoined left and right internal gl (2,C) phase increments over a spaeetime increment ea. Our action Sg measures the covering nurnber of the spinor phases over spacetime M\ U D j; the Dj ate singular domains or caustics, where J = 1, 2, and-3 chiral pairs of spin waves cross.Here, the rnassive Dirac equations emerge to govern the mass scattering that keep the "null zig-zags" of a bispinor particle confined to a timelike worldtube. We identify the coupled envelopes of 1, 2, and 3 chiral bispinor pairs as the leptons, mesons, and hadrons, respectively.These source topologically---nontrivial gl (2, C) phase distributions in the far-field region, which appear as effective rector potentials. Their vorticities ate the spin eurvatures, whose Herrnitian parts--the gravitational curvatures--speeify how our spacetime manifold 1Vi must expand and curve to accornmodate such anholonomic differentials. The anti-Hermitian parts reproduce the standard electroweak and strong ¡ together with their actions. Lg also contains sorne new cross terrns between electroweak potentials and gravitational curvatures. Do these signal a failure of unitication, or predict new phenomena?