The book contains 24 selected, revised and thoroughly edited papers addressing various issues of propulsion physics written by world-known experts. The papers include critical analyses of previous studies and controversial aspects of novel propulsion concepts, new theoretical and experimental results and findings as well as numerous references to archival publications worldwide. The book is organized in 8 chapters: (1) Liquid Propulsion; (2) Hybrid and Solid Propulsion; (3) SCRAMJet and Pressure-Gain Combustion; (4) Gas Turbine Propulsion. The volume was prepared as a reference for research scientists and practicing engineers in the field of aerospace propulsion.