There is September 11 and then there are the days after, and finally the years. <P><I>Falling Man</i> is a magnificent, essential novel about the event that defines turn-of-the-century America. It begins in the smoke and ash of the burning towers and tracks the aftermath of this global tremor in the intimate lives of a few people.<P>First there is Keith, walking out of the rubble into a life that he'd always imagined belonged to everyone but him. Then Lianne, his es-tranged wife, memory-haunted, trying to reconcile two versions of the same shadowy man. And their small son Justin, standing at the window, scanning the sky for more planes.<P>These are lives choreographed by loss, grief and the enormous force of history.<P>Brave and brilliant, <I>Falling Man</i> traces the way the events of September 11 have reconfigured our emotional landscape, our memory and our perception of the world. It is cathartic, beautiful, heartbreaking.