See also my review of Empire & Ecolitan
An enormously powerful fleet of starships arrives above a far-future Earth, an Earth once the home of a near legendary human Empire, which has now, apparently, collapsed into a contrite, pastoral, shadow of its former self.
Sound at all familiar? Shame on you if it doesn't, because it's the basis of at least half the stories that A. E. van Vogt ever wrote. Fortunately, Adiamante seems to have taken the bare bones of classic van Vogt and reworked it with a '90s dash of ecology and cultural relativism, bringing everything bang up to date, whilst reinforcing the old adage that great sf has nothing to do with the way we will be in the future and everything to do with the way we are now.
The newly arrived fleet is a race of militant cyborgs (not dissimilar to the Borg), descended from the long-exiled survivors of a genocidal war against the "demis" - the van Vogtian superhumans who now live on the remains of the Earth. The cybs, as they are known, are the archetypal Prodigal Son; except for their mission to visit the sins of the fathers upon their distant descendants.
The majority of the novel is a gradual and engrossing introduction to both cultures, depicting the slow ballet of diplomacy as each pretends to believe the lies of the other - or are they lies? It's a subtly played game, smoothly narrated with a deceptive ease, building to a cathartic climax that is pure Tragedy in the air of awful inevitability that permeates events from page one.
Modesitt, like van Vogt, writes easily of technological miracles, but his have conversely more of the technology and less of the miraculous about them. That they are used by humans, not superhumans, and that the wisdom needed to accompany this use has been (or not been, as we see) extremely hard won in human terms, gives Adiamante a modern resonance which seems lacking today in van Vogt's work.
I missed my stop on the bus, forgot to phone my mother and stayed up till the wee small hours on a school-night reading Adiamante; and it was well worth it.