2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/95616This paper provides an elementary introduction to the basic concepts used in describing epitaxial crystal growth in terms of the thermodynamics and kinetics of atomic steps. Selected applications to morphological instabilities of stepped surfaces are reviewed, and some open problems are outlined.To appear in the Proceedings of the Oberwolfach workshop on Multiscale Modeling in Epitaxial GrowthMaterials ScienceStatistical Mechanicstext