Moonfall Trilogy Series by Heather Spears, Tesseract Books

Tasman is born into a world populated by two-headed bicephalic "twins" who share one body. Alone, she struggles for acceptance and becomes the unwitting key to the Earthas salvation, in a poetic and apocalyptic vision of the future where technology exists as a mere remnant of a destroyed world, conjoined twins are the norm and the orbit of the moon is decaying.

In the far future, deadly radiation from atomic conflict has caused humanity to mutate into two-headed or bi-cephalic people, who are essentially twins inhabiting one body. In the Moonfall series, readers follow one-headed Tasman and her family, witnessing their development from outcasts to heroes, the only ones able to fit into the ancient spaceships and save the Earth from the threat of the moon's unstable orbit... moreIn the far future, deadly radiation from atomic conflict has caused humanity to mutate into two-headed or bi-cephalic people, who are essentially twins inhabiting one body. In the Moonfall series, readers follow one-headed Tasman and her family, witnessing their development from outcasts to heroes, the only ones able to fit into the ancient spaceships and save the Earth from the threat of the moon's unstable orbit. The Taming, sequel to Moonfall and The Children of Atwar, concludes the epic saga of humanity's strange future. less