It always confused me that Andre Norton's first novel about the Stellar Patrol (1953) should deal with its demise. For that is what this excellently crafted novel deals with, the end of that noble service after 1000 years as guardians of peace and order in the First Galactic Empire.
It is a time of decadence and dissolution in the Empire. Sector wars are carrying off more and more worlds from Central Control. Individual bureaucrats are usurping their positions to carve out private kingdoms. Only the incorruptible Patrol and its Code remain to stand in their way. Yet, the Patrol has seen better days. Their ships are old and there are no replacements- only cannibalization keeps them running. The supply ships come less and less often. Communications between sectors- and with Central Control itself is breaking down. There are fewer and fewer new recruits. The only thing still as strong as ever is the dedication, honor, and tradition of the Patrol.
Specifically, this is the story of the last voyage of the Vegan Scout, Starfire. She was sent on a final, futile mission, along with her sister ships to remap and rediscover forgotten worlds near the galactic rim. In reality, she has been sent out by an ambitious Imperial bureaucrat to die- yet due to their ancient trust and loyalty the patrol obeys. Her Patrol crewmen and elite Rangers (think of them as Marine Scouts, but with finely trained telepathic powers) finally crash land on a world so ancient that all record of it has been lost. But sometimes endings come full circle- and beginnings are found and restored....
If there had been no other creator of hard science fiction, or of fantasy, in the second half of the 20th century, Andre Norton would have been enough.