Young writer Olive Wellwood, her sister Violet and husband, Humphry, live in a charmed home in the countryside with their seven children, though we follow most closely the older two, Tom, who is a sort of "lost" child more at home in the woods, and his more practical and determined sister Dorothy. Olive is a famous writer of children's books, in the golden age of fiction about children, inventing fairy tales drawn from her reading of folk tales and fantasy, observation of her children's lives, the magic of the Kent landscape and pieces of her own childhood. After her husband resigns his position with a bank, Olive becomes the chief breadwinner for the family. In addition to her published work, she creates for each child a private story, bound in a special journal. Byatt describes several of those books, but she unlocks the one for Tom, Olive's oldest son, with devastating effect. The story -- about a boy who loses his shadow and must search for it underground -- closely mirrors Tom's internal and psychological life. When she mines her son's story for a new play, "Tom Underground," a darker take on the motifs of Peter Pan, her son becomes truly lost. When asked by a journalist to explain the private children's books, Olive says: " 'Well, I sometimes feel, stories are the inner life of this house. A kind of spinning of energy. I am this spinning fairy in the attic, I am Mother Goose quacking away what sounds like comforting chatter but is really -- is really what holds it all together.' She gave a little laugh, and said 'Well, it makes money, it does hold it all together.' " Behind the public story of Olive and Humphry's marriage is a series of private indiscretions, including some startling revelations. On the surface, middle-class Victorian and Edwardian England may have been obsessed with appearances and propriety, but as with every age, all-too-human desires lurk just underground. Secret passions electrify the stories of the other families, too ... There's an investment banker and his German wife and their anarchist son; the mercurial Arts and Crafts ceramicist Benedict Fludd and his addled family; and a widowed military man whose Cambridge Apostle son is struggling with his homosexuality. Add to this heady mix a true lost boy who escaped from a pottery factory and is discovered hiding below the Victoria and Albert Museum ...