  For a disordered system near the Anderson transition we show that the
nearest-level-spacing distribution has the asymptotics $P(s)\propto \exp(-A
s^{2-\gamma })$ for $s\gg \av{s}\equiv 1$ which is universal and intermediate
between the Gaussian asymptotics in a metal and the Poisson in an insulator.
(Here the critical exponent $0<\gamma<1$ and the numerical coefficient $A$
depend only on the dimensionality $d>2$). It is obtained by mapping the energy
level distribution to the Gibbs distribution for a classical one-dimensional
gas with a pairwise interaction. The interaction, consistent with the universal
asymptotics of the two-level correlation function found previously, is proved
to be the power-law repulsion with the exponent $-\gamma$.
