Hour of the Horde
by Gordon R. Dickson
The voracious and merciless Horde roved the galaxies, stripping whole star systems of all life. As they advance on the Milky Way, a galaxy-wide force is hastily arrayed to stop them. But Miles Vander, the warrior sent by Earth to join the defense, must first convince his alien crewmembers that he is just as good a soldier as they.