In this work we present the results of a study of spectral statistics for a
classically integrable system, namely the rectangle billiard. We show that
the spectral statistics are indeed Poissonian in the semiclassical limit f
or almost all such systems, the exceptions being the atypical rectangles wi
th rational squared ratio of its sides, and of course the energy ranges lar
ger than L-max = h/T-0, where T-0 is the period of the shortest periodic or
bit of the system, however L-max --> infinity when E --> infinity.