Dawnman Planet — Mack Reynolds

Ron Bronston was sworn to protect the United Planets' dream - the pursuit of freedom and progress on all of the 3000 human-inhabited planets of the galaxy. As an operative of the secret section of the United Planets' Bureau of Investigation, Bronston was called upon for some very unusual missions. But the present crisis was without precedent. Man's sovereignty in his galaxy was challenged by a single madman and the super-weapons of the Dawnmen, the mysterious aliens from the unexplored vastness of the galaxy's center. Bronston, alone, had to find a way to stop them.