ABSTRACT
Gravitational lensing-i.e. light deflection by gravity-has become, in the last few years, one of the most important fields in present-day astronomy. The enormous activity in this area has mainly been driven by the considerable improvements in observational capabilities. Due to the new wide-field cameras and telescopes which are already in place or will become operational in the near future the rate and quality of the lensing data will increase dramatically. As gravitational lensing is independent of the nature and physical state of the deflecting mass, it is perfectly suited to study dark matter at all scales.
