  We describe Monte Carlo models for the dynamical evolution of the nearby
globular cluster NGC 6397. The code includes treatments of two-body relaxation,
most kinds of three- and four-body interactions involving primordial binaries
and those formed dynamically, the Galactic tide, and the internal evolution of
both single and binary stars. We arrive at a set of initial parameters for the
cluster which, after 12Gyr of evolution, gives a model with a fairly
satisfactory match to the surface brightness profile, the velocity dispersion
profile, and the luminosity function in two fields. We describe in particular
those aspects of the evolution which distinguish this cluster from M4, which
has a roughly similar mass and Galactocentric distance, but a qualitatively
different surface brightness profile. Within the limitations of our modelling,
we conclude that the most plausible explanation for the difference is
fluctuations: both clusters are post-collapse objects, but sometimes have
resolvable cores and sometimes not.
