To be the offspring of genius, even if not everyone considers it genius, must make growing-up even more difficult than it is for most of us. And to write a novel about the process, which involves creating someone whom your readers can believe in as a genius, is even more difficult. That is what Mrs. Byatt has tackled in her first novel, Shadow of a Sun….

It is easy to be somewhat cynical about the earnest sensitivity with which Mrs. Byatt explores … tortured relationships—she is a very feminine writer, careful to give us not only the visual detail (which she does very well) but also the emotional convolutions behind each utterance of her characters, which a tougher, more experienced writer would have pruned. She luxuriates in tentative similes and asides which hold up the dialogue…. But these are not disastrous faults, because Mrs. Byatt feels deeply for...