By Light Alone by Adam Roberts

Set in a future where humanity has evolved to photosynthesize, eliminating the need for food, the story explores the societal divide between the wealthy, who still indulge in traditional consumption, and the impoverished, who rely solely on sunlight. The narrative follows a wealthy family whose daughter is kidnapped, unraveling a complex web of class struggle, privilege, and the human condition. As the characters navigate this altered world, they confront the moral and ethical implications of their existence, questioning the true cost of progress and the essence of humanity itself.

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