We review theoretical and simulational approaches to the description of
equilibrium bulk crystal and interface properties as well as to the
nonequilibrium processes of homogeneous and heterogeneous crystal nucleation
for the simple model systems of hard spheres and Lennard-Jones particles. For
the equilibrium properties of bulk and interfaces, density functional theories
employing fundamental measure functionals prove to be a precise and versatile
tool, as exemplified with a closer analysis of the hard sphere crystalliquid
interface. A detailed understanding of the dynamic process of nucleation in
these model systems nevertheless still relies on simulational approaches. We
review bulk nucleation and nucleation at structured walls and examine in closer
detail the influence of walls with variable strength on nucleation in the
Lennard-Jones fluid. We find that a planar crystalline substrate induces the
growth of a crystalline film for a large range of lattice spacings and
interaction potentials. Only a strongly incommensurate substrate and a very
weakly attractive substrate potential lead to crystal growth with a non-zero
contact angle