In this book, attention centers on the Enzmann Echolance, which for the first time addresses and elegantly solves the crucial reaction-mass problem: how a starship can radically reduce its burdensome load of reaction mass – the material it ejects rearward – while still retaining enough fuel plus reaction mass to accelerate itself to velocities near that of light, and subsequently to decelerate. This book concludes by noting that the construction and launch of Echolance fleets can be accomplished without major technological breakthroughs, at surprisingly affordable cost, in a relatively short time, and with beneficial consequences for humans who remain on the Earth, as well as for those who open up the cornucopia of interstellar space. This is a call for action.