Gravitational lenses can provide crucial information on the geometry of the
Universe, on the cosmological scenario of formation of its structures as well
as on the history of its components with look-back time. In this review, I
focus on the most recent results obtained during the last five years from the
analysis of the weak lensing regime. The interest of weak lensing as a probe of
dark matter and the for study of the coupling between light and mass on scales
of clusters of galaxies, large scale structures and galaxies is discussed
first. Then I present the impact of weak lensing for the study of distant
galaxies and of the population of lensed sources as function of redshift.
Finally, I discuss the potential interest of weak lensing to constrain the
cosmological parameters, either from pure geometrical effects observed in
peculiar lenses, or from the coupling of weak lensing with the CMB.Comment: To appear Annual Review of Astronomy and Astrophysiscs Vol. 37. Latex
and psfig.sty. Version without figure, 54 pages, 73Kb. Complete version
including 13 figures (60 pages) available on ftp.iap.fr anonymous account in
/pub/from_users/mellier/AnnualReview ; file ARAAmellier.ps.gz 1.6 M
