A Door into Ocean is the novel upon which the author's reputation as an important SF writer principally rests. A ground-breaking work both of feminist SF and of world-building hard SF, it concerns the Sharers of Shora, a nation of women on a distant moon in the far future who are pacifists, highly advanced in biological sciences, and who reproduce by parthenogenesis--there are no males--and tells of the conflicts that erupt when a neighboring civilization decides to develop their ocean world, and send in an army.

all-female world

The pristine city of Elysium floats on the water world of Shora, inhabited by 'immortals' who have succeeded in unlocking the secrets of life. Outsider Blackbear Windclan wants to share the secret of immortality with his own people, but can he, and the City of Elysium, survive the corruption and decadence that immortality has bred into the ageless society. And what of the consciousness of self-aware nano-sentient servitors and their quest for vengence?

Multiple cultures: one matriarchal (with corresponding language) and non-white, one is the all-female Sharers from A Door Into Ocean, and the other accepts same-sex relations freely.

Only children can colonize the planet Prokaryon, genetically modified for a world whose chemistry kills unaltered adults. A colony of orphans struggles to survive, and finds the planet hides strange secrets. The Prokaryan landscape is ordered, as if by unseen gardeners, hidden "masters" no human has ever found. The weather behaves as though designed to meet the planet's needs. When fire threatens a forest, a rainstorm appears, only to dissipate when the fire is put out. When a ruthless corporation threatens to terraform Prokaryon, to recreate it for "normal" humans, there is a sudden urgency to find the intelligent life form directing the planet. For only then can the colonists save their world—and reveal unexpected possibilities for the human future.

Diverse cast