Valy sent photos and letters before the war. (Courtesy of Sarah Wildman)
Sarah Wildman, an award-winning journalist, is author of "Paper Love: Searching For the Girl My Grandfather Left Behind."

Years ago in Berlin, I met a Jewish woman with four fingers on one hand. She held up the appendage, her finger not exactly missing, but torn off, just below the knuckle. The accident that maimed her saved her life, she told me. She had been a factory worker, a forced laborer in Berlin. The day the digit was mangled in 1943, she was sent to the hospital, so she was absent when her entire factory was sent to Auschwitz. She survived through luck and wits and the grace of do-gooders, especially one valiant non-Jewish woman who took her in. The survivor’s name is Hanni Levy. She was 19 when she lost that finger. She’s in her late 80s today.

Her story is like the ones told by so many other survivors – improbable, amazing. And perhaps what makes it most remarkable is hearing it from the woman herself. Hanni has lived in Paris since the war; her English is peppered with French. She is the kind of woman to whom the adjective “sparkling” would be aptly applied. She wore deep red glasses, a color to which her hair was closely matched.

For decades now, survivors of the Holocaust have told these stories – to students, to teachers, to anybody willing to listen — and in the process turned the past into something almost tangible: memory. A living witness does not dryly recite facts and statistics; she recalls her life. She uses body language, intonation and eye contact to convey meaning. She makes history real.

The Nazis had very specific goals: to exterminate the Jews and other “undesirables,” of course, but also to erase them. Render them forgotten. In Paris I met survivors of camps where Jewish slaves were forced to burn the personal items of all those deported from the City of Light – diaries, notebooks, photographs – to render them, literally, unmemorable.

It took time for remembering to begin. In the years immediately after the Holocaust, people were reluctant to hear the stories, and survivors were hesitant to tell them. The trauma was just too close. But over the last 30 years, as “bearing witness” became a mantra, we have come to rely on memory and on narrative as a means of taking in the enormity of the horror.

Now, as the last eyewitnesses to the Holocaust leave us, we face an enormous loss. The personal connection made the tragedy that is otherwise so very large, nearly tactile, almost graspable. How well can we learn about what happened without these powerful emotional tethers to tie us to it? Will the Holocaust mean as much to young people when they can’t hear from the woman who escaped her train to Auschwitz? What happens when the Holocaust becomes as dusty and distant as the Civil War? Will the Nazi project — to render Jews and other victims unmemorable — meet belated, unfortunate, success?

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There is a partial solution to this problem. Years ago, I discovered a folded note, of the kind we all passed in the pre-texting era, tucked inside an old photo album in my grandfather’s study. In each quadrant of the note was a pasted-in selfie from the 1930s, a photo of a girl. “Will Karl write to me today?” she wondered, her face open, happy, the words written in the paper below each picture.

Karl was my grandfather; the girl in the photos was not my grandmother. The note was dated May 1939, 10 months after Karl escaped Vienna in 1938, and she mailed it from Berlin to him in America. He had preserved this note, as well as other letters from her — hundreds and hundreds of words, the story of a life upended — in a collection of letters mislabeled “Patient Correspondence A-G.” Her name was Valerie “Valy” Scheftel. She was a doctor, like him. She had been his lover. And she was alone in Berlin, desperate to get out of the Reich. He had moved here and, eventually, started a family. But for decades he preserved their life together by saving their correspondence. Their romance is the subject of my just published book, “Paper Love: Searching for the Girl My Grandfather Left Behind.

We like to believe we are adept at remembering. We excel at memorials. Americans — and American Jews, in particular— have spent millions of dollars on enormous buildings commemorating the Holocaust. But it is not the marble alone, or the grandiose gesture, that enables us to remember: It is the individual stories and the small details that give the Holocaust its uniqueness, its universality and its resonance into the future. As the eyewitnesses to the apocalypse of the 20th century leave us, museums and teachers and universities are seeking ways to explain the horror to the next generation. Some proposals are futuristic – projecting holograms of speaking survivors into rooms – but the most, and the best, are old fashioned: reading, seeing, using words and text set against the artifacts of lives.

Letters, affidavits, passports, keepsakes — these are the tactile tools to show what people experienced. They will have to be our witnesses when witnesses are gone. Valy’s words are so raw, so evocative and so modern; they are relatable. She writes of feeling she’s in “hibernation,” waiting for her U.S. immigration number to come up. She writes of waiting, an endless waiting, to return to normal life. In Berlin, she tells my grandfather, there are no young people left, and life feels old to her. Her youth feels far away. She describes, despite the censors who read her letters, a world closing in on her, diminishing her, making her old before her time. She was only 26 when my grandfather left Europe.

Yad Vashem, the Israeli national Holocaust museum, is bringing together these types of documents under a project called “Gathering the Fragments.” It is rushing to gather material while there are still people who can give the full context and identification for each photo, each artifact and each letter. The Holocaust Museum in Washington, too, is aggressively collecting materials – from survivors, but also from onlookers and bystanders. The materials are decaying and their owners are dying. (The two museums, as well as the Shoah Foundation at the University of Southern California, have also recorded thousands upon thousands of oral histories.)

Now is our last chance to record the remaining diaries and notes and photos and stories of the six million. These are the artifacts that tell the stories of real people — neither rich, nor poor, neither art owners, nor big names — who experienced this war, who carried the stories of those they left behind, and who, often as not, tucked away for decades entire family archives in attics and basements and boxes, unwilling or unable to reexamine the past. These are the people the Nazis wanted to erase. Preserving these documents is an act of rebellion 70 years in the making. The words and photographs and individual stories tell of a genocide that was accomplished life by life.

In my family’s case, my grandfather did not tell us what he had saved before he died. I can’t know for sure if he purposefully mislabeled the box his letters and artifacts were kept in, but I suspect it was not an accident. Yet even with all these secrets, in the end he didn’t want them destroyed – perhaps because the box held, in addition to Valy’s letters, the stories of dozens of those left behind as the Nazis took city after city.

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When I began working on a book about my grandfather and his Viennese girlfriend, I learned that an Israeli cousin’s father, Reuven Ben-Shem, had kept a daily journal of his time in the Warsaw ghetto, a day-by-day look at the devastation of his people, his own family, his life. He describes the dead on the street, the anxiety of parents, the terror. “We all feel that a terrible period is approaching, perhaps the end of our days,” he wrote, as translated by Laurence Weinbaum. “There is a desire to be enlisted, to mount some kind of defense, some kind of war, but I see just how much the public’s strength has decreased and how its energy has been depleted.”Reuven wrote 800 page of meticulous, tiny Hebrew, a reporting project of horror. He died in 1980. (His eldest child, a piano prodigy, was smuggled to safety on the Aryan side – only to die there.) But his words are as fresh and devastating today as they were when he was starving, in the ghetto.

My grandfather kept all of the letters of his exploded Viennese world — from dozens of friends, cousins, half-siblings and his own lover, all desperately trying to leave. Some were able to flee – to Budapest, to Shanghai, to Palestine, to Australia, to Brooklyn. But for many others, these words were their last recorded. Their efforts, their anxiety, their anger, their despair, and even their occasional triumph, open a window onto a moment in time even though the writers and recipients of their words have long since left this world. He kept those missives for more than half a century, tucked away, unseen. And he wasn’t alone.

The memorial for those people shouldn’t, and won’t, be cast in stone. It will be written in paper and ink. Tactile, personal, important.