Talk title: Cosmology with gravitational lensing by clusters of galaxies

Gravitational lensing by clusters has emerged as a powerful cosmological
probe, enabling mapping of dark matter and constraining dark energy. I will
present lensing tests of some the key aspects of the cold dark matter paradigm
ranging from abundance of substructure, properties of density profiles - inner and
outer slopes and central concentration, tidal stripping and constraints on the nature
of dark matter. Cluster strong lensing can also be used to constrain dark energy models.
I will present new results using simulated clusters that  demonstrate that this technique
could be competitive with others to probe the geometry of the Universe. The feasibility of
this technique as well as its limitations and its power to discriminate between evolving
and non-evolving  dark energy equations of state will be presented. I will conclude with
the future prospects for cluster lensing.