The Newtonian limit of solutions of a model problem is studied. It is
shown that under certain assumptions on the initial data relativistic
solutions approach a Newtonian solution as the speed of light tends to
infinity. The model problem, although having a much simpler structure
than the ''real'' equations, shows many of the typical problems arisi
ng in the discussion of the Newtonian limit. The method of characteris
tics is applied and its limitation discussed.