There exist very few exact solutions to practical Stefan problems. The key solutions are presented in the first section for both one- and two-phase systems. Approximate solution techniques are then presented, including the use of boundary fixing transformations, perturbation methods, small and large time solutions, and Heat Balance Integral Methods. The use of these methods is illustrated through the study of laser-induced sublimation. Although the book does not focus on numerical techniques, a topic that could occupy a whole book, a brief description of the main methods (with references) is presented in the final section.