Final installment--the individual entries (Brightness Reef, 1995; Infinity's Shore, 1996) aren't particularly intelligible in their own right--of Brin's vast yam 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 nco-chimps and nco-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.