Testing Cosmology with Gravitational Lensing

Dark mass-energy may be "seen" directly via its coherent gravitational lens distortion of the forest of high redshift galaxies. Tomographic inversion of these cosmic mirages in deep wide-field imaging surveys enables a unique 3-d view of our universe: images of assemblies of dark matter and their development over time provide clues to the process of structure formation in the universe. The mass overdensity spectrum and "cosmic shear" correlations as a function of look-back time, when combined with microwave background anisotropy probes of the early universe, will soon lead to precision cosmology and test our fundamental assumptions. The notion that dark matter may be self-interacting will be discussed in the context of recent data. The Deep Lens Survey, and plans for the Large-aperture Synoptic Survey Telescope will be reviewed.