  The character of critical behavior in physical systems depends on the range
of interactions. In the limit of infinite range of the interactions, systems
will exhibit mean-field critical behavior, i.e., critical behavior not affected
by fluctuations of the order parameter. If the interaction range is finite, the
critical behavior asymptotically close to the critical point is determined by
fluctuations and the actual critical behavior depends on the particular
universality class. A variety of systems, including fluids and anisotropic
ferromagnets, belongs to the three-dimensional Ising universality class. Recent
numerical studies of Ising models with different interaction ranges have
revealed a spectacular crossover between the asymptotic fluctuation-induced
critical behavior and mean-field-type critical behavior. In this work, we
compare these numerical results with a crossover Landau model based on
renormalization-group matching. For this purpose we consider an application of
the crossover Landau model to the three-dimensional Ising model without fitting
to any adjustable parameters. The crossover behavior of the critical
susceptibility and of the order parameter is analyzed over a broad range (ten
orders) of the scaled distance to the critical temperature. The dependence of
the coupling constant on the interaction range, governing the crossover
critical behavior, is discussed
