This novel originally appeared in Analog in two parts under the titles Ultima Thule and Pistolero

Milk run. That’s what they told Ronny Bronston this job would be. “Just like a vacation,” his boss had said. All he and the giant Dorn Horsten would have to do is visit the planet Einstein and see if there was any reason not to admit them to United Planets. The planet was a paradise, where the people had bred themselves for intelligence and beauty, where everyone was completely free. Free, sometimes, to get into more trouble than they could handle. Only Ronny could get them out of that trouble; and that’s how he wound up on the Dawnworld, in a gladiator’s arena!