In Future Spacecraft Propulsion Systems the authors demonstrate the need to break free from the old established concepts of expendable rockets, using chemical propulsion, and to develop new breeds of launch vehicle capable of both launching payloads into orbit at dramatically reduced cost, and for sustained operations in low-Earth orbit. The next steps, they explain, to establishing a permanent "presence" in the solar system beyond Earth are the commercialisation of sustained operations on the Moon, and the development of advanced nuclear or high-energy space propulsion systems for solar system exploration out to the boundary of interstellar space. In the future, high-energy particle research facilities may one day yield a very high-energy propulsion system that will take us to the nearby stars, or even beyond. This is a timely and comprehensive book, putting spacecraft propulsion systems in perspective.