From The Art of Michael Whelan:
"John Brizzolara's novel*of the same title is about a confrontation between extraterrestrials and humans, and humankind's attempt at domination. Caught up in this struggle and all the internal conflicts of the native politics, there is one man who comes to live with the natives and learn about them on a personal level. The tension of their interaction provided me with the approach I chose for the cover.
The clue to who wins in the end is in the spear 'sticking it' to the earthlike stone embedded in the macrame."