Medium-future Martian odyssey from the author of Anvil of Stars (1992), etc. In 2171, Mars inhabitants are grouped in extended family businesses that sometimes compete, sometimes cooperate, and resist the imposition of a central authority. But Earth is forever trying to impose its will upon Mars; and so young politician-to-be Casseia of the old and powerful Majumdar family--following a brief and painful affair with ambitious, brilliant physicist Charles Franklin--will travel to Earth with her uncle Bithras to negotiate with the powers that be. Unexpectedly, the talks fizzle; worse, Casseia learns that Earth has infected Mars's artificial- intelligence "thinkers" with virus-like "evolvons." With Earth now openly hostile, Mars must present a united front, and Casseia is elected Vice President. She realizes that what has alarmed Earth are the discoveries of Charles Franklin: his physics of "descriptors" allow the alteration or "tweaking" of matter and energy within the absolute-zero Bell Continuum. In practical terms: instantaneous communications, the ability to fry remote targets instantaneously, even the moving of entire planets! Earth attacks by activating the evolvons that sabotage Mars's thinkers, producing chaos. Charles Franklin's team retaliates, and the attack ceases. Clearly, though, this is just the first phase of a struggle that must result in Mars's subjugation--or its leaving the solar system altogether. Mundane politicking, plotting, and characters combined with stunning and remarkable invention and extrapolation. Bear is an infuriating writer in that his narrative skills never come close to matching the sheer brilliance of his ideas. So it has been; so it is here.