Atomic-level simulations are providing powerful insights into the properties of ferroelectric materials. In particular, we illustrate the effect of the strong coupling among the dipole moment, strain, and microstructure (both physical and chemical) in thin films, nanostructures, superlattices, and solid solutions of ferroelectrics. We assess the domain of validity of the atomic-level approach relative to other theoretical and computational approaches. We identify the strengths and weaknesses of the current generation of interatomic potentials and suggest strategies for improving their performance. We also identify application areas in which atomic-level simulation promises to play an important role.