This book presents the basics of flame propagation, emphasizing the combustion of ethanol, hydrogen, and ammonia, which are fuels that could make combustion sustainable. Its eight chapters cover fundamentals such as thermodynamics of combustion, chemical kinetics, conservation equations, premixed flames, flame dynamics, compressible flow, detonations, and flammability limits. The book emphasizes important theoretical developments of flame propagation fundamentals and the significance of biofuels and alternative fuels with practical examples using ethanol, hydrogen, or ammonia, making the content directly applicable to real-world scenarios. Advanced undergraduate and graduate students, researchers, and practicing engineers in combustion, sustainable energy, transport phenomena, thermodynamics, and related fields will welcome this fundamental and practical textbook.