  We review the Parisi-Frisch MultiFractal formalism for
  Navier--Stokes turbulence with particular emphasis on the issue of
statistical fluctuations of the dissipative scale. We do it for both Eulerian
and Lagrangian Turbulence. We also show new results concerning the application
of the formalism to the case of Shell Models for turbulence. The latter case
will allow us to discuss the issue of Reynolds number dependence and the role
played by vorticity and vortex filaments in real turbulent flows.
