  We have developed an algorithm to find haloes in an N-body dark matter
simulation, called VOBOZ (VOronoi BOund Zones), which has as little dependence
on free parameters as we can manage. By using the Voronoi diagram, we achieve
nonparametric, `natural' measurements of each particle's density and set of
neighbors. We then eliminate much of the ambiguity in merging sets of particles
together by identifying every possible density peak, and measuring the
probability that each does not arise from Poisson noise. This probability could
be interpreted as a measure of a halo's sub-haloness, and might be of use to
researchers of the halo model. The first parameter in VOBOZ controls the
subtlety of particle unbinding, and may be eliminated if one is cavalier with
processor time; even if one is not, the results saturate to the parameter-free
answer when the parameter is sufficiently small. The only parameter which
remains, an outer density cut-off, does not influence whether or not haloes are
identified, nor does it have any effect on subhaloes; it only affects the
masses returned for supercluster haloes.
