THE VOYAGE might not have begun that way for Nathaniel, Eliot, and Andrew, but it could have. Telling what could have happened is the best Sybil Braithwaite can do. She will never be able to say “This is how it was” with the historian’s or biographer’s confidence; there isn’t a soul left for her to interview. The people who took part in her story are dust, their memories sucked with their lives into the boundless abyss of the past. Nor is there a wealth of written records, so Sybil has had to fill in the vast empty spaces in the chronicle by making things up, big things as well as little things, like the way the weather was on a given day, how the sky looked, what people said, did, thought, and felt; the clothes they wore. In this way, she has tried to recapture the tenor of a vanished time, to reanimate extinguished lives, and reconstruct what happened that summer ninety-seven years ago. She hopes that her version of events, its archipelagos of fact, connected by long bridges of fiction, is truthful. Imagination, she will tell you (as she’s told me), is not an unreliable sextant, if you’re trying to get a fix on the truth. And in matters relating to her family’s history, she can be very imaginative, possessing a gift (so she claims) that is the opposite of prophesy: on the scantiest evidence—an entry in a diary, an old photograph, a few lines from a letter—she can see things that occurred long before she was born; she hears people, decades in their graves, speaking again, and all with such clarity that she does not seem to be imagining but remembering. She relies on her instincts to tell her if what she imagines (or remembers) is true—not necessarily factual but true. It somehow has to feel right.