Sherry Tepper is one of the great female sci fi writers. This is not her best work but is still a good read.
From Library Journal
As a force of unknown origin sweeps across the universe, depopulating human-colonized planets in its wake, linguist Lutha Tallstaff travels to the planet Dinadh in search of noted adventurer Leelson Famber, whom she believes may be able to help. Set on a planet where mysterious religious practices hide a terrifying covenant between its inhabitants and the godlike power they worship, this novel offers disturbing insights into humanity's place in the cosmos. Strong characters with personal dilemmas-whose resolutions have far-reaching consequences-add depth and immediacy to the story. Another elegant piece of work from master storyteller Tepper (Beauty, LJ 8/91), this volume belongs in most libraries.
With such world-building epics as A Plague of Angels , Tepper has secured a reputation for uniquely combining elements of science fiction and fantasy that she maintains in her latest novel by delving into both mythmaking and original scientific speculation. It tells the story of Dinadh, an isolated, human-populated world surrounded by dead planets. A century ago, an unknown force or race known only as the Ularians mysteriously wiped humanity off all the planets within several light-years of Dinadh. Now the unseen Ularians have returned, and the Earth-led Alliance is asking Lutha Tallstaff to return to Dinadh to track down her missing former lover, Leelson Famber, who alone may hold the key to the Ularians' identity. Tepper makes brilliant use of alternating first- and third-person narration and also of fanciful supporting characters, such as Snark, a criminal whose punishment as a "shadow" involves constant, full-sensory monitoring by the Alliance. Although not one of Tepper's best, Shadow's End shows that her skill at inventing new cultures and their citizenry remains impressive. Carl Hays