At the heart of this stimulating and provocative study is a science fiction story by James Tiptree Jr (Alice Sheldon-Bradley, 1916-1987) about a brother and a sister (and 58 other human beings) who encounter an alien while on a starship travelling to discover a habitable planet. The book includes an outline of Tiptree's work and of her remarkable life as the only child of jungle explorers, as a painter, an American agent during and after World War II, an experimental psychologist, and a female science fiction writer in male disguise.