A chapbook of a story originally published in 1953, it's the tale of a television series, KNOW YOUR UNIVERSE!, looking for new sensations for flagging ratings.
Wilbur Murphy is sent to the planet Sirgamesk to investigate the tale of the Horseman of Space, a figure that rides up on a horse from the planet to greet incoming spaceships, no spacesuit in evidence and a planet with no horse.
An airless world settled by Javanese, Arabs, and Malay, the people lived in the valleys, airtight roofs sealing out the vacuum. The surrounding lands held million year old ruins from the time of an atmosphere.
Wilbur gets more than he bargained for, landing in the middle of a crowded valley. The Sultan wants to open more valleys, but his son, The Prince, thinks it will cost to much. Why build the expensive roofs when there were already valleys with roofs?
A fine Vance story.