  We discuss the status of Monte Carlo simulations of (mainly finite
dimensional) spin glass systems. After a short historical note and a brief
theoretical introduction we start by discussing the (crucial) 3D case: the warm
phase, the critical point and the cold phase, the ultrametric structure and the
out of equilibrium dynamics. With the same style we discuss the cases of 4D and
2D. In a few appendices we give some details about the definition of states and
about the tempering Monte Carlo approach.
