This poetic historical novel, set between the world wars, tells the story of an American couple and their adopted son, Lightfoot. Fos, a chemist intrigued with constellations, bioluminescence and x-rays, returns from the war in France and falls in love with Opal, the daughter of a glassblower on the Outer Banks of N.C. They move to Knoxville, where Fos and an army buddy have a photography studio, and travel to summer fairs with Fos's x-ray machine. When Opal inherits a farm on the Clinch River, they move again, and live happily with Lightfoot, who had been abandoned, until the property is claimed for a TVA dam. In 1941, Fos gets a job at the Oak Ridge Laboratory-Site X in the government's race to build the bomb. Their lives proceed from innocence and fascination with things that glow to the day in Aug. 1945 when the atomic bomb is dropped over Hiroshima. But when Opal falls ill with radiation poisoning, Fos's great faith in science deserts him. Marianne's writing is powerful and hypnotic, and the lives of her characters beautifully follow the arc of 20th century American life and belief.