With the changing technological environment, the aircraft industry has experienced an exponential growth. Owing to the escalating use of aircrafts nowadays, it is required for the professionals and learners of the field to have conceptual understanding of propulsion systems and ability to apply these concepts in a way to develop aircrafts that make them fly further, higher and faster. Designed as a text for the undergraduate students of Aerospace and Aeronautical Engineering, the book covers all the basic concepts relating to propulsion in a clear and concise manner. Primary emphasis is laid on making the understanding of theoretical concepts as simple as possible by using lucid language and avoiding much complicated mathematical derivations. Thus, the book presents the concepts of propulsion in a style that even the beginners can understand them easily. The text commences with the basic pre-requisites for propulsion system followed by the fundamental thermodynamic aspects, laws and theories. Later on, it explains the gas turbine engine followed by rocket engine and ramjet engine. Finally, the book discusses the introductory part of an advanced topic, i.e., pulse detonation engine. KEY FEATURES OF THE BOOK ? Coverage of all major types of propulsion systems ? Focus on specific systems and sub-systems of gas turbine engine in individual chapters ? Possesses pedagogical features like chapter-end important questions and suggested readings