Second part of Robinson's Martian trilogy, following the stunning Red Mars (1993). Now, at the beginning of the 22nd century, Mars is again being exploited by the metanationals (what the transnational corporations, now fewer and larger and often running entire countries on Earth, have become), acting under the guise of the United Nations Transitional Authority. Meanwhile on Earth -- overpopulated, polluted, and short of resources -- wars have become commonplace. Only William Fort of Praxis metanational has the foresight to want to help both planets, and so he sends negotiator Art Randolph as his ambassador to the Martian underground. The Martians, a quarrelsome complex of groups ranging from radical Reds to bewildered recent emigrants, agree on only one thing: Mars must gain its independence -- but this time the revolution must avoid violence and occur, as far as possible, by consensus. Throughout the human struggle, the face of Mars continues to change as the atmosphere thickens, the temperature rises, seas form, and plants spread along the chasms and craters. Robinson introduces new characters, like Jackie and the tall, charismatic, Mars-born Nirgal, to join Red fanatic Ann, battler Maya, scientist Sax, the treacherous Phyllis, and organizer Nadia. Green doesn't quiet reach the sublime heights of Red, but the same virtues -- deep thought, fascinating detail, life-sized characters, an engrossing narrative -- are present. Robinson's achievement is impressive, and Blue Mars is still to come.