The first (not self-contained) part of a projected far-future trilogy. Planet Jijo, once inhabited by the advanced alien Buyur, is now occupied by five alien species along with humans. Each race, hoping to find some elbow room in an increasingly crowded Five Galaxies, took up residence illegally; each race sank its spaceships in the oceans, then made elaborate plans to eradicate all traces of themselves once Galactic investigators show up--as they eventually will. So the arrival of a spaceship throws the entire planet into turmoil, especially when the ship proves to contain not Galactics but humans--who are thought to be gene pirates in search of valuable DNA, as such, they will have every reason to leave no witnesses when they depart. Brin carries the action forward via a multiplicity of viewpoints: the alien, Asx, of the Commons, a multiracial council of elders; scholar Sara; the Stranger, a mysterious human found burned and brain-damaged; hunter Dwer; the rebellious Rety; the young alien, Alvin, and his party of would-be alien scientists; and the heretic, Lark, whose task is to establish liaison with the newcomers and learn their real purpose. Typical Brin (Glory Season, 1993, etc.): tremendously inventive, ambitious work undercut by excess verbiage, one-dimensional characters, and drably unevocative writing.