By the author of The Clearing (1982) and other novels of suspense and marital conflict, an attractively styled chronicle of the dissolution of a marriage, as the familial threads binding spouses, and parents and children, slowly snap amid the summer's beauty and autumn's danger on Nantucket island. Philip, an orderly, contained ""product of all those New England teachers and lawyers,"" has announced to his artist-wife Estrella--an open, pragmatic woman with a volcanic temper--that he's walking out on their 25-year marriage. He's fallen in love with loner Jane, also an anthropologist. Eventually he'll persuade Jane to spend the rest of the summer on Nantucket, so he can be near his children: Liddy, who'll return from England, 16-year-old Chrissy, and seven-year-old Jasper. Estrella accuses him of ""circling like a vulture,"" but, one by one, the cool and distant Liddy, vulnerable Chrissy, and little Jasper will meet with Dad. The children, shaken, will try each other's limits, while Estrella, in a fury, still feels a ""pang of pain"" at a remembered touch. In the meantime, Jane is helpless before Phil's obsession with his family, while Phil, aroused by Jane's vulnerability, even blames his children for withdrawing from his reservoir of tenderness, thereby making an affair with Jane ""inevitable."" The advent of a major hurricane at last defines the separation as absolute and final, in spite of the absent father's ""white knight"" dash to save the family--who've learned to survive without him. Interspersed among the skirmishes are Chrissy's essays on African animal life--and one is free to draw conclusions. (The children here are alarmingly precocious.) A family can be, as Chrissy writes about hers, ""like the Wallendas making a human pyramid suspended in air on nothing but a fine rope."" This is the tale of what happens when one member of the team steps out.