  The aim of this paper is to review and discuss qualitatively some results on
the properties of amorphous packings of hard spheres that were recently
obtained by means of the replica method. The theory gives predictions for the
equation of state of the glass, the complexity of the metastable states, the
scaling of the pressure close to jamming, the coordination of the packing and
the pair correlation function in any space dimension d. The predictions compare
very well with numerical simulations in d=3 and somehow also in d=2. The
asymptotic predictions for d->oo are within the rigorous bounds. The theory can
be extended to binary mixtures and to hard core potentials with an attractive
tail or square well.
