  In a previous paper, we have shown that the classical and quantum
relativistic dynamics of the Stueckelberg-Horwitz-Piron [SHP] theory can be
embedded in general relativity (GR). We briefly review the SHP theory here,
and, in particular, the formulation of the theory of spin in the framework of
relativistic quantum theory. We show here how the quantum theory of
relativistic spin can be embedded, using a theorem of Abraham, Marsden and
Ratiu, and also explicit derivation, into the framework of GR by constructing a
local induced representation. The relation to the work of Fock and Ivanenko is
also discussed. We show that in a gravitational field there is s highly complex
structure for the spin distribution in the support of the wave function. We
then discuss entanglement for the spins of a two body system.
