Final installment--the individual entries (Brightness Reef, 1995; Infinity’s Shore, 1996) aren’t particularly intelligible in their own right--of Brin’s vast yarn about planet Jijo and its six alien races, all illegal immigrants living in terror of a visitation from the rulers of the Five Galaxies. The general idea is that the galaxy’s older and wiser species, or “patrons,” like to “uplift” lesser races—that is, raise them into full sentience by providing extra brains, speech mechanisms, and suchlike. So, from Earth come not only humans but uplifted neo-chimps and neo-dolphins, too. Brin does provide a cast list and a glossary, whereas even for regulars a plot summary would have been much more useful. Since Brin wrote the charming and inspiring The Postman (1985), his novels have grown ever more impenetrable and overambitious; like the rest of the trilogy, this one’s hard to get into, hard to follow, and difficult to care about.