  Dictated by Symmetry Principle, string theory predicts not General Relativity
but its own gravity which assumes the entire closed string massless sector to
be geometric and thus gravitational. In terms of $R/(MG)$, i.e. the
dimensionless radial variable normalized by mass, Stringy Gravity agrees with
General Relativity toward infinity, but modifies it at short distance. At far
short distance, gravitational force can be even repulsive. These may solve the
dark matter and energy problems, as they arise essentially from small $R/(MG)$
observations: long distance divided by much heavier mass. We address the
pertinent differential geometry for Stringy Gravity, stringy Equivalence
Principle, stringy geodesics and the minimal coupling to the Standard Model. We
highlight the notion of `doubled-yet-gauged' coordinate system, in which a
gauge orbit corresponds to a single physical point and proper distance is
defined between two gauge orbits by a path integral.
