  A hundred years ago, two British expeditions measured the deflection of
starlight by the sun's gravitational field, confirming the prediction made by
Einstein's General theory of Relativity. One hundred years later many
physicists around the world are involved in studying the consequences and use
as a research tool, of the deflection of light by gravitational fields, a
discipline that today receives the generic name of Gravitational Lensing. The
present review aims to commemorate the centenary of Einstein's Eclipse
expeditions by presenting a historical perspective of the development and
milestones on gravitational light bending, covering from early XIX century
speculations, to its current use as an important research tool in astronomy and
cosmology.
