The Sharers of Shora are a nation of women on a distant moon in the far future. They are pacifists, they are highly advanced in biological sciences, and they reproduce by parthenogenesis - because there are no males. Conflict erupts when a militaristic neighboring civilization decides to develop their ocean world and sends in an army.
A groundbreaking work both of feminist science fiction and of world-building hard science fiction, A Door into Ocean is the novel that made Joan Slonczewski's reputation as an important science-fiction writer.