  Three dimensional self-gravitating systems do not evolve to thermodynamic
equilibrium, but become trapped in nonequilibrium quasistationary states. In
this Letter we present a theory which allows us to a priori predict the
particle distribution in a final quasistationary state to which a
self-gravitating system will evolve from an initial condition which is
isotropic in particle velocities and satisfies a virial constraint 2K=-U, where
K is the total kinetic energy and U is the potential energy of the system.
