Tensor-vector-scalar-modified gravity: from small scale to cosmology
  The impressive success of the standard cosmological model has suggested to
many that its ingredients are all one needs to explain galaxies and their
systems. I summarize a number of known problems with this program. They might
signal the failure of standard gravity theory on galaxy scales. The requisite
hints as to the alternative gravity theory may lie with the MOND paradigm which
has proved an effective summary of galaxy phenomenology. A simple nonlinear
modified gravity theory does justice to MOND at the nonrelativistic level, but
cannot be consistently promoted to relativistic status. The obstacles were
first sidestepped with the formulation of TeVeS, a covariant modified gravity
theory. I review its structure, its MOND and Newtonian limits, and its
performance in face of galaxy phenomenology. I also summarize features of TeVeS
cosmology and describe the confrontation with data from strong and weak
gravitational lensing
