Amy Ellis Nutt is a science writer on the National staff at The Washington Post. Her beat is the brain.

Before iPhones and thumb drives, before Google docs and gigabytes of RAM, memory was more art than artifact. It wasn’t a tool or a byproduct of being human. It was essential to our character and therefore a powerful theme in both myth and literature.

At the end of Book 2 of the “Divine Comedy,” with Paradise nearly in reach, Dante is dipped into the River Lethe, where the sins of the self are washed away in the waters of forgetfulness. To be truly cleansed of his memories, however, Dante must also drink from the river of oblivion. Only then will he be truly purified and the memories of his good deeds restored to him. Before we can truly remember, according to Dante, we must forget.

In “Patient H.M.: A Story of Memory, Madness, and Family Secrets,” author Luke Dittrich seems to be saying that before we can forgive, we must remember. The terrible irony is that H.M., the real-life character around whom Dittrich’s book revolves, had no memory at all.

In prose both elegant and intimate, and often thrilling, “Patient H.M.” is an important book about the wages not of sin but of science. It is deeply reported and surprisingly emotional, at times poignant, at others shocking.

"Patient H.M.: A Story of Memory, Madness, and Family Secrets" by Luke Dittrich (Random House)

H.M., arguably the single most important research subject in the history of neuroscience, was once Henry Molaison, an ordinary New England boy. When Henry was 9 years old, he was hit by a bicyclist as he walked across the street in his home town, Hartford, Conn. It was the mid-1930s, and the accident probably triggered years of epileptic seizures, which grew more frequent and more severe as Henry grew up. In 1953, at the age of 27 and facing a lifetime of disability, Henry underwent a risky brain operation. Though it was unclear exactly where Henry’s seizures originated in the brain, his surgeon, William Beecher Scoville, targeted a suspected spot deep in the medial temporal lobes and removed all but a vestigial amount of a sea-horse-shaped structure called the hippocampus. The good news: Henry’s seizures were greatly reduced. The bad news: It quickly became clear that the young man had paid a life-altering price for the diminution of those seizures. For all intents and purposes, he was now memory-less.

In the middle of the 20th century, the human brain was still largely a mystery. Memory, it was believed, was distributed throughout a person’s gray matter. But when Henry awoke from his operation and was found to be incapable of forming new memories, science learned a valuable lesson about the crucial role the hippocampus played in a person’s life. Though he would live 55 more years, Henry would be forever amnesic for those years, unable to recall the names of people he met and the places he visited, any thought he had, any action he took. And yet his losses were neuroscience’s gain.

If this was the sole subject of “Patient H.M.” the book would still be a fascinating read, since Dittrich, a magazine writer by trade, spent six years writing it, poring over medical records and transcripts and interviewing key figures to flesh out a story that’s never been told this fully.

But “Patient H.M.” has delicious surprises in store for the reader. It turns out that Scoville, the surgeon who forever altered Henry’s life and the history of neuroscience, was the author’s grandfather. Brain operations have always been a last resort in cases of severe epilepsy. When they are performed, a patient receives only a local anesthetic because as the surgeon probes for the site of the seizures, he or she must make sure not to damage critically important brain functions. The easiest way to do that is to keep patients awake and periodically ask them questions. “As my grandfather made that final cut, Henry lay there, looking up at him. He could catch glimpses of his mask, of his surgical cap, of his headlamp. He could see his glasses, those thick-rimmed surgical loupes with their magnifying lenses. He could hear my grandfather’s breathing, feel his warm exhalations.

“And maybe, just maybe, some sweat or blood or condensation cumulated on a lens of those glasses, and maybe my grandfather asked a nurse to reach over and wipe it clean. . . . Maybe that’s why, for the rest of his life, Henry would tell people that he’d once dreamed of being a brain surgeon but had decided against it, because he wore glasses, and what if his glasses got dirty and a nurse attempting to clean them knocked them askew, causing him to make the wrong move, to cut too far, to go too deep. . . .

“My grandfather didn’t make any mistakes that day.

“He took exactly what he wanted to from Henry.”

What was taken from Henry after his surgery, and how he was treated as a research subject for more than half a century, are just two of the provocative questions Dittrich takes up in his book. Because it is about so much more, Dittrich takes risks with the structure, never more so than when he leaves Henry on Page 47 and doesn’t return to him until Page 201. The discursion is what lends the book its power and keeps the reader turning its pages. In fact, Scoville, Dittrich’s grandfather, often steals the show. A daredevil, relentlessly curious and unafraid of breaking boundaries, he built a prominent neurosurgical practice in which he often performed lobotomies, the surgical technique of quieting the severely mentally ill.

Threaded throughout the stories of H.M. and Scoville are important side trips into the history of neuroscience, mental illness and the treatment of humans as research subjects. One horrifying tidbit: Walter Freeman, the Pennsylvania physician who perfected the prefrontal lobotomy, performed more than 2,400 during his career, traveling across the country to do them in a camper he called the “Lobotomobile.” As Dittrich notes, Freeman sometimes performed as many as 25 lobotomies a day, teaching other physicians the “ice pick” technique, which involved entering the brain through the easiest route: the eye socket. Lobotomies, the reader learns, were performed into the 1970s, thanks in part to Scoville.

But it’s his portrait of Suzanne Corkin, the M.I.T. scientist who oversaw decades of research on H.M., acting sometimes as a guardian and others as a scientific gatekeeper, that has drawn Dittrich into controversy. Until she died in May at the age of 79, Corkin was best friends with Dittrich’s mother. This gave Dittrich unusual access to Corkin, though she rebuffed him numerous times before finally agreeing to be interviewed. Those interviews, and the details of what amounted to a custody battle over the ownership and disposition of Henry’s brain after his death, paint a complex picture of Corkin.

With her privileged access, she’d built a career on studying H.M. The proprietary nature of that research, and her protectiveness toward H.M. and his brain, made it incumbent on Dittrich to gently question her personal and professional motivations.

In combing through Dittrich’s interviews with Corkin, some of which he includes, verbatim, in the book, those motivations remain largely ineffable. It’s Corkin’s scientific mentor, Brenda Milner, the first researcher to test H.M., who comes closest to explaining the peculiarities of a long-term scientific relationship with an amnesiac: “ ‘We found ourselves beginning to regard him the way you would regard a pet,’ Milner once told an interviewer. ‘He lost his humanness. You can’t build a friendship or any sort of human affection for the person.’ ”

On Aug. 7, the New York Times Magazine published an excerpt from “Patient H.M.” that dealt largely with Corkin’s claim to have destroyed all ancillary data about H.M., as well as her contentious relationship with Jacopo Annese, founder of the Institute for Brain and Society in San Diego and the scientist who was awarded the postmortem task of processing, preserving and analyzing H.M.’s brain. At the heart of the conflict is a dispute over one of Annese’s early findings, which could undermine the integrity of research based on H.M. The next day, Corkin’s colleagues at M.I.T. as well as some 200 other scientists sent separate letters to the Times criticizing the publication of what they deemed errors in Dittrich’s description of Corkin’s actions and attitudes.

It’s too bad the scientists didn’t wait to read the book when it was released the next day. If they had, they would have discovered that those errors were largely differences of interpretation and emphasis, and that Corkin takes up only a fraction of the book. The real shame of it is that they would have also realized that “Patient H.M.” is a scintillating book, infused with humanity.

Patient H.M.
A Story of Memory, Madness, and Family Secrets

By Luke Dittrich

Random House. 440 pp. $28