(From the publisher):
To the man of the starship Quetzal their task seemed routine: to establish diplomatic relations and enter into trade negotiations with the people of a newly discovered planet. Since to all appearances the folk of Gwydion were the most thoroughly amiable in all the galaxy -- words for such concepts as war, theft, anger, murder and jealousy did not even exist in their language -- there could hardly be a problem. But as the season changed on Gwydion, so did the people...
Later published as The Night Face
Original title: Let the Spacemen Beware!
Genre: Fiction→ Science Fiction→ Political→ Interspecies Federation