We the Underpeople — Cordwainer Smith

In a far-flung future, planoforming ships knit together a galaxy ruled from Earth by the ruthless benevolence of the mysterious Lords of the Instrumentality, who presided over a utopia without death, danger-or freedom. The Underpeople, humanlike beings created from animals to do the work of utopia, had no rights, and could be disposed of at the whim of a human. But they had become more humanlike than their creators, and their leader, the cat woman C'Mell, had a plan for gaining their freedom-which made her much too dangerous a person to be permitted to live. Elsewhere in the galaxy, the planet Norstrilia had power of its own, for it was the only source of stroon, the drug which arrested aging and made humans immortal. Its inhabitants were wealthy beyond comprehension, and one of them, a boy named Rod McBan, with the help of his computer, had manipulated the galactic economy until he completely owned the planet Earth-which made him much too dangerous a person to be permitted to live. But when Rod came to Earth and joined forces with C'Mell and the Underpeople, the petrified utopia of the Instrumentality began to crack and fall apart as freedom was reborn in the galaxy. . . .