In the 22nd century, humankind has colonized the solar system. Starflight is possible but hugely expensive, so humakind's efforts are focussed on Isis, the one nearby Earthlike world. Isis is verdant, Edenic, rich with complex DNA-based plant and animal life. And every molecule of Isian life is spectacularly toxic to human beings. The entire planet is a permanent Level Four Hot Zone. Despite that, Isis is the most interesting discovery of the millennium:...