Nicola Griffith's first novel, Ammonite was published in 1993, with ISBN 0-345-37891. It won both the Lambda Literary Award for LGBT (lesbian, gay, bisexual, transgendered) fiction, and the Tiptree Award for science fiction with themes of gender identity.

Ammonite is the story of Marghe Taishan, an employee of the sinister, monolithic 'Company', sent to the planet GP (pronounced 'Jeep') as an anthropologist. The distinctive feature of Jeep is an endemic disease which kills all men (and some women) who contract it. Marghe makes a journey across Jeep, living with many of its indigenous cultures. She is enslaved by the nomadic Echraide, and then reaches the quieter village of Ollfoss, where she joins a family, learns the mystic discipline of linking, and eventually becomes a 'viajera', or traveling wise woman.

Although the narrative voice never refers to any characters as lesbians, it is assumed that most of the natives of Jeep can form sexual relationships with other women. Marghe also forms a sexual relationship with a member of her adopted family, Thenike.

Ammonite falls into a tradition of science fiction stories that deal with worlds where everyone belongs to a single gender: Tiptree's Houston, Houston, Do You Read? is a notable example.