  In this talk I will review some of the recent applications of the replica
theory to glasses. I will firstly describe the basic assumptions and I will
show that they can be considered as a precise reformulations of old ideas. The
relation of this approach with the mode-coupling theory will be shortly
discussed.
  I will present numerical simulations for binary mixtures. The results of
these simulations point toward the correctness of the replica approach to
glasses. I will describe the results of off-equilibrium simulations for large
systems, in which the aging dynamics is studied.
