The Margarets by Sheri S. Tepper
Publication Date: 2007-06-01
The only human child living in a human work colony on the Martian satellite Phobos, little Margaret Bain has devised a system for keeping the suffocating demons of boredom and loneliness at bay: She invents six imaginary companions, each an extension of her own personality, to play with. When the unproductive Phobos project is shut down, and after Margaret is forced to return to Earth with her parents, the child's other selves are lost to her. But they are not gone.
Left behind, each one flourishes--refining its own persona, acquiring its own history--before ultimately dispersing to far-flung destinations throughout the universe. On a near-barren homeworld denuded by thoughtless-ness and chemistry, Margaret grows to adulthood and marries, despite the seemingly utter hopelessness of humanity's future. The Earth is so impoverished that its inhabitants must import water and other basic necessities of life--trading the only viable product the planet has left to offer ... slaves.
The time will come when Margaret must leave this world as well, expelled as part of a desperate survival plan millennia in the making--an astonishing scheme that will require her to gather together the many Margarets who are now scattered throughout the galaxy. The creator of the Margarets must now bring all her selves home ... or watch her race perish.