Nonlocal General Relativity
  A brief account of the present status of the recent nonlocal generalization
of Einstein's theory of gravitation is presented. The main physical assumptions
that underlie this theory are described. We clarify the physical meaning and
significance of Weitzenb\"ock's torsion, and emphasize its intimate
relationship with the gravitational field, characterized by the Riemannian
curvature of spacetime. In this theory, nonlocality can simulate dark matter;
in fact, in the Newtonian regime, we recover the phenomenological Tohline-Kuhn
approach to modified gravity. To account for the observational data regarding
dark matter, nonlocality is associated with a characteristic length scale of
order 1 kpc. The confrontation of nonlocal gravity with observation is briefly
discussed.
