Saturn’s Race by Larry Niven

The future is a strange and dangerous place. Chaz Kato can testify to that. He is a citizen of Xanudu, a city-sized artificial island populated by some of the wealthiest men and women on future Earth. A place filled with hidden wonders and dark secrets of technology gone awry. Lenore Myles is a student when she travels to Xanadu and becomes involved with Chaz Kato. She is shocked when she uses Kato’s access codes to uncover the grizzly truth behind Xandu’s glittering facade.
Not knowing who to trust, Lenore finds herself on the run. Saturn, a mysterious entity, moves aggressively to break the security breach. With interests of the world’s wealthiest people at stake, and powerful technology at it’s fingertips, Saturn, puts Lenore racing for her life, against a truly formidable foe.