Combustion of condensed systems is characterized by a complex interplay of physical and chemical forces occurring at high temperatures and in short timescales. The book contains a review of the approaches used in combustion modeling of energetic materials including mono and double base propellants. Combustion models for homogeneous and heterogeneous systems are briefly described along with critical analysis of the main assumptions. Analytical and numerical approaches for studying steady-state and transient combustion regimes are presented. The applicability limits of the models are discussed as well as the methods of their validation. The book can be useful for students, researchers, engineers and technologists specialized in the field of developing and designing the new chemical propulsion systems.