Book excerpt: From the foreword by Dr. rer. pol. Erik Kolek This book is about the physical foundations of interstellar space travel. Interstellar space travel involves traveling between stars, such as between our sun and Proxima Centauri. Humanity, or rather its technologies, are still at the very beginning of the technological development series, and the same applies to the physical foundations. The latter must be listed and explained step by step in order to make traveling between the stars possible, at least in theory.