Jennifer Egan has written a rich, brilliant, capacious new historical novel called Manhattan Beach. What on earth made her do it?

From the beginning of her career, Egan’s fiction has been experimental and enigmatic, hovering just at the outer edge of realism. The book that made her seriously famous, the Pulitzer Prize-winning 2011 novel A Visit From the Goon Squad, had a chapter made up of PowerPoint slides. It also had a tender heart; her clever manipulations of convention, designed in her early work to demand uneasy questions of the reader, softened into a means of contemplating transience and mortality.

Manhattan Beach (Scribner, 433 pp., ***½ out of four stars) picks up those themes — but in a traditional, occasionally even sentimental fashion.

The book (which has been long-listed for the National Book Award) is set for the most part in New York during World War II, where a young woman named Anna Kerrigan works as part of the war effort at the Brooklyn Naval Yard. She has a difficult life (her father is missing, her sister severely disabled) but she has a vision, too. From her window she can see the Navy’s divers in the river, and her soul leaps toward them — she wants to dive.

The novel’s second major character is Anna’s father’s old employer, a dashing nightclub owner named Dexter Styles. By his marriage and foresight he has managed to go mostly clean. “He liked the thought that his own power would one day be refined into translucence,” Egan writes, “with no memory of the blood and earth that had generated it.” When his path crosses Anna’s, though, that ambition comes into doubt.

Egan has every gift a writer can possess, and like all of her work Manhattan Beach is radiant with intelligence, special simply because it’s by her. Take Anna’s determination to become the Navy’s first female diver: the best…