This book is about building craft for space travel—a space travel that is not in the distant future but in the immediate future. There is no question that we have the technology to build and power large craft capable of traversing the galaxy, and for now, this book will focus on achieving the goal of intragalactic travel. We will describe various methods of power generation and propulsion, delineate the materials and technology for construction, discuss the building of the spacecraft from the outside in, and show what is required to sustain life on the craft for extended periods of time. While we will go into some detail on each of these, pointing out advantages and disadvantages to components and methods, this is not, nor is it intended to be, a highly technical book to be used by specialists. Rather it is intended to inform the general readership about what is possible, and perhaps what is not, in building and operating spacecraft for long-distance and long-duration travel with current and available means.. NOTA: El libro no está en español, sino en inglés.