The first murder victim in P. D. James’s latest (and perhaps last) novel is a great writer who is keenly aware that his powers of mind and imagination are fading. Surveying a universe he perceives as empty and unfeeling, Nathan Oliver wants to shout, “Don’t take away my words! Give me back my words!” James herself has no need to utter such a cry. At 85, she has written one of the best books of her long and distinguished career.

On its surface this is a most traditional of English mysteries, involving a small group of people brought together in an isolated setting, in this case a tiny private island called Combe, 12 miles off the coast of Cornwall. Once a pirate hideout and then a way station for slaves transported to the New World, Combe in its present incarnation is a lovely, peaceful place where powerful people come for a respite from their stressful lives. The small permanent staff works to ensure the comfort and privacy of visitors—never more than five of whom are in residence at a time. In addition, two people with a connection to the island inhabit two of its six stone cottages: Emily Holcombe, the last of the family that for centuries had owned Combe, and, for two months of the year, Nathan Oliver, one of England’s greatest novelists and the last remaining person to have been born on the island.

When Oliver’s body is discovered hanging from the lighthouse’s top story, Scotland Yard’s poet-detective Adam Dalgliesh and his retinue are dispatched to the island to investigate. It’s a murder, of course, a murder that must be solved quickly and discreetly, since the prime minister wants to hold soon a high-level conference on the island.

Oliver was generally disliked, with good reason, but who could have had a motive for murder? The answer, Dalgliesh thinks, lies in the past. But which past? In the small part the island played in World War II? Or in some other, more private past?

Dalgliesh’s investigations are brought to a halt when he becomes ill with SARS, brought to Combe by one of the guests, the German ambassador to China, recently retired. Dalgliesh’s deputies, Kate Miskin and Francis Benton-Smith, carry on. But it is Dalgliesh himself who, from his sickbed, solves the case with careful reasoning and an inspired flash of insight—though not before a second murder occurs. This is a well-plotted, satisfying mystery, with enough red herrings to keep readers guessing.

What makes the book remarkable is the complexity and psychological depth James brings to her characterizations and the mythical and literary substructure she gives her story. The latter is never intrusive, but it gives the book a resonance and depth that take it far beyond the confines of its genre. Combe itself suggests many things: a treasure island offering peace and restoration to those wise enough to seek them; a fallen world redeemed and then again in need of redemption; a seemingly secure Eden unable to keep itself uncontaminated by the world’s contagions.

Literary allusions abound, most notably to Shakespeare’s The Tempest and Charles Dickens’s Oliver Twist. These give an added dimension to one of James’s most fascinating creations, Nathan Oliver, a man whose nature and creativity are as much of a mystery as is the puzzle of who killed him.

A writer of genius whose books illuminate the human heart, Oliver is himself heartless. He stunts and enslaves his daughter, Miranda, and performs cruel experiments on people so that he can observe their behavior and accurately describe it in his novels. Yet Oliver’s secretary and editor, Dennis Tremlett, truly mourns him. He realizes that although Oliver has never seen him as more than a servant, “together they had engaged in the profound and mysterious adventure of language. In Oliver’s company he had become alive.”

We seldom speak of mystery novels as having a theme, but this one is unified by its concern for the plight of mistreated and rootless children—and the adults they become. Oliver was raised by a violent and drunken father. Miskin still struggles with the effects of having been an illegitimate child raised in poverty by a resentful grandmother. The few young people on the island have suffered similar deprivations. Reflecting on his experiences on Combe, Benton-Smith quotes W. H. Auden’s poem “September 1, 1939”: “I and the public know / What all schoolchildren learn, / Those to whom evil is done / Do evil in return.” But James gives Miskin the last word: “Not all of them. Not all the time. But they don’t forget, and they do pay.”

The novel’s final pages will be bittersweet to James’s many fans, for they sound very much like a farewell. As Dalgliesh and his associates prepare for their return to London, they realize that their stay on the island has subtly transformed them. Dalgliesh, so long an austere and lonely figure, is joyfully planning his marriage to Emma Lavenham. And Miskin has come to terms with the unhappy past that has haunted her throughout the series and has let go of her hope that Dalgliesh might one day return her love. She realizes that “perhaps for her, too, the future could be rich with infinite possibilities.”