For a disordered system near the Anderson transition we show that the
nearest-level-spacing distribution has the asymptotics P(s)βexp(βAs2βΞ³) 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<Ξ³<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 βΞ³.Comment: REVTeX, 8 pages, no figure