“The Cloud of Unknowing,” by Thomas H. Cook; Harcourt, 310 pages; $24.

People are dead; the author lets us in on that from the start. But who? And why?

David Sears is in custody, but is he a suspect or just a witness? We wait with him in a cell in a small New England town until he is summoned to a spare interrogation room. There, Detective Samuel Petrie starts his tape recorder and asks Sears to tell his story.

“You don’t know where to begin,” David thinks. “There is so much to tell, so many currents in the river.”

Sears begins not with recent events but with childhood memories of his father, a paranoid schizophrenic who “strung together a living” writing book reviews and substitute teaching, and who demanded that David and his sister, Diana, memorize and recite long passages of classical literature.

“His students were beneath him,” David explains, “as were the lowly, salaried teachers who, he said, pursued their modest pensions like scraps of holy writ. His contempt was bottomless, and it erupted in fits of spiraling rage.”

This is not what Petrie wants to hear. He has a dead body (or is there more than one?) that must be explained, and he wants rational answers to simple questions. But soon, it is clear that Sears must tell the story in his own way.

Promptly we learn, with Petrie, that David had always been haunted by the fear that his father’s illness would be passed down to him, his sister and their children. The fear was realized when Diana’s son, Jason, was diagnosed with childhood schizophrenia.

Her husband, a geneticist on the verge of a breakthrough that never seems to arrive, saw the boy as a distraction and wanted to institutionalize him. When Jason was found dead at the bottom of a pond, police declared it an accident; but Diana, without a shred of evidence, was convinced that her husband killed him.

David describes how his sister “investigated” by researching ancient bog murders in England, by studying accounts of people who hear stones speaking to them, and by pursuing the idea that the Earth is a living creature that can give evidence of her son’s murder.

With this premise established, the story unfolds in the interrogation room, the reader listening in with a growing sense of dread about what Diana, her husband, and even David, might have done.

“The Cloud of Unknowing,” Thomas H. Cook’s 16th novel, is a superbly structured tale written in an elegant, literary style. Although it is being marketed as a crime novel, it doesn’t resemble anything you are likely to find on bookshop mystery shelves.

This is a book that examines family mythology, genetic determinism, the line between sanity and madness, the difference between intuition and hallucination.

Ask yourself: If Diana hears voices whispering that her son was murdered, is she crazy if the voices are right?