Low-ranking diplomat Jame Retief, whose satirically wild sf adventures have been amusing readers for nearly 20 years, finds suitable solutions to confusing interstellar problems despite the determined idiocy of his protocol-bound, status-seeking superiors. And though his full-length appearances (in contrast to the short stories) have often proved disappointing, this is a better-than-average affair--about the backward, wormlike Furtheronians: the Crawlies and their rivals the Creepies, who apparently are bombarding each other with stone cannon balls and conducting daily counter-invasions. But nobody knows why the Furtheronians are fighting, or even how to tell the Crawlies from the Creepies: the intrepid Terran peace mission, led by Ambassador Pouncetrifle and Retief's superior, Counsellor Magnan, ineffectually distributes Terran largesse in the form of Yankee Stadium-type sports arenas; once again the Terrans are opposed by the hissing, five-eyed, lobsterish Groaci, who retaliate with Bolshoi-type ballet theaters. So, naturally, it's up to Retief to expose the Groaci's grasping machinations and bring peace. The first few chapters are the most smile-worthy (""welcome to Furtheron, and pay no heed to these boulders crashing through the roof--merely a quaint native custom, it appears""); but even when the hilarity subsides, there are genial compensations in the improbable plot-twists and slapstick action.