The Overlord's Thumb

The Overlord's Thumb is a science fiction novella by Robert Silverberg, first published in 1958. It follows Colonel John Devall, who leads a Terran mission on the alien planet Markin, as he faces a moral dilemma when his nephew, Lieutenant Paul Leonards, accidentally kills an alien during a botanical expedition. The alien society demands Leonards be tried for murder and blasphemy, forcing Devall to choose between asserting Earth's dominance or respecting the alien culture. The story explores themes of cultural interaction and the complexities of moral responsibility in human-alien encounters.