While just about every race uses a different means of achieving it, nearly all forms of faster-than-light travel relies on a certain phenomenon: the Onion Theorem. If you apply just the right sort of force to a physical object, you could project it into a sub-dimension, or subspace as it was more frequently called. This was an environment that corresponded exactly with the normal universe, except that it is smaller. Submerge, travel a mile, and surface, and you would find that you had traveled a dozen miles. Complicated as that was, it was only the beginning. For there were levels within levels. You could push deeper, to realms that were even smaller, and where the travel differential was even greater. Theoretically, if you could dive deep enough, you could emerge anywhere in the universe at the same time as you left your previous location. This was the Holy Grail of space drive engineers, which they had named the blink drive. No one has ever developed a drive that could even come close.