I must not stay to notice the strange fortunes of all the many other quasi-human worlds. I will mention only that in some, though civilization was destroyed in a succession of savage wars, the germ of recovery precariously survived. In one, the agonizing balance of the old and the new seemed to prolong itself indefinitely. In another, where science had advanced too far for the safety of an immature species, man accidentally blew up his planet and his race. In several, the dialectical process of history was broken short by invasion and conquest on the part of inhabitants of another planet. These and other disaster, to be described in due course, decimated the galactic population of worlds.