  In hierarchical models of gravitational clustering, virialized haloes are
biased tracers of the matter distribution. As discussed by Mo & White (1996),
this bias is nonlinear and stochastic. They developed a model which allows one
to write down analytic expressions for the mean of the bias relation, in the
initial Lagrangian, and the evolved, Eulerian spaces. We provide analytic
expressions for the higher order moments as well. We also show how the Mo-White
approach can be extended to compute the evolution, not just of the haloes, but
of the dark matter distribution itself.
  The model predictions for the mean and scatter in the Eulerian bias relation,
as well as for the Eulerian halo-mass and halo-halo correlation functions, are
in reasonable agreement with numerical simulations of hierarchical
gravitational clustering for haloes of a wide range of masses, whereas the
predictions for the corresponding Lagrangian quantities are accurate only for
massive haloes.
