  The most simple observed cases of gravitational lensing of distant quasars
and galaxies by galaxies and clusters of galaxies are used to test Einstein's
theory of General Relativity and Newtonian Gravity over galactic and
intergalactic distances. They extend the distance range over which
Newton-Einstein Gravity has been tested by 10 orders of magnitude. Although the
precision of the tests are far from the precision of the solar system tests of
EGR and those from pulsar timing in close binary systems, they confirm quite
accurately the validity of Einstein's General Relativity and its weak field
limit, Newtonian Gravity, over galactic and intergalactic distances and the
existence of large quantities of dark matter in galaxies and clusters of
galaxies. Future observations can improve the accuracy of the tests and reduce
the possibilities for systematic errors.
