We've all been there, when we think about our grandparents: too often, we have left it too late to ask the right questions, and a generation's secrets and stories disappear.
But, in the past few years, some families have taken matters beyond the pedestrian question-and-answer and, instead, publish entire books about their history.
Joseph Szlezinger, who now lives in Hampstead, north London, is a child survivor of the Holocaust in Belgium. A tall and robust octogenarian, his book, Shattered Dreams to New Beginnings is dedicated to his beloved grandchildren "in the hope that in the future, when I am no longer here, my memories will live on through them".
He embarked on the book at the urging of his wife Kathrin, who wanted him "to put something on paper". The couple were introduced to Julie Wheelwright, who had already worked with another family to produce a privately published family memoir.
Wheelwright, the director of two MA programmes in creative writing at London's City University, is an award-winning writer and historian who, though not Jewish, has "a particular interest in Jewish history".
She engrossed herself in documenting the minutiae of Joe Szlezinger's family history - but even though she was also doing her PhD at the time, neither she nor Joe anticipated that the project would take five years.
The resulting book, with many stops and starts over the years, is a meticulously researched account of Joe's family history, setting the lives of his parents and grandparents in context in eastern Europe. Joe survived largely thanks to a devoted group of Belgian Catholics who hid many Jewish children in a convent until the end of the war. His mother Gita also survived and the two came to England and painstakingly rebuilt their lives.
There were some days, Joe admits, "that I just didn't want to talk about it". He was never able to find out the ultimate fate of his father but he assumes he was murdered in a death camp. Wheelwright follows every part of his "fantastic, rich story" as far as she can - but Joe concedes that this is not a route for everyone. "Not everyone is up for going down memory lane", he says. "I cried a lot during the telling of my story, but in a way it was therapeutic".
The Szlezingers had 350 copies of his book made but so many people outside the immediate family circle have asked to read it that they are now hoping to benefit three charities - Chai Cancer Care, Great Ormond Street Hospital and Shaare Zedek Hospital in Jerusalem - from additional proceeds.
Joe says he is really happy to have done the book. As for Julie Wheelwright, she says: "I learned so much from doing this. It's not just about Jewish history, but about how memory and trauma work".
At a conference in Sao Paolo, Brazil, Wheelwright met Edvaldo Pereira Lima, a writer and journalist engaged in a parallel project, to bring to life in book form the story of another Joseph, Joseph Davidowicz.
Joseph Davidowicz and the Diaspora is the life story of a Jew born in Lodz, Poland, in the 1930s. Pereira Lima who, like Wheelwright, is not Jewish, says: "At first, the Davidowiczes wanted a private thing, just books for family members and friends. The idea was to print about 200 copies or so.
"However, I was successful in making them agree that the book would be a way not just to honour Joseph's life, but could be a bridge to the new generation of Brazilian Jews, giving them a good and sound background of their grandparents' ordeal and struggle to make their lives run smoothly in a new culture and country. It would be also a way to honour all the Jewish community".
The family agreed. The book - written at the instigation of Joseph's wife, Zofia - is now out in Brazil as a commercial publication as part of the "Clube de Autores", an on-demand platform wherein books are printed as they are purchased.
The research and interviews took Pereira Lima about a year, fitting them in around his other work - he is the director of an independent graduate course in literary journalism, the only one of its kind in Brazil. The Davidowicz story is one of a true wandering Jew, from Poland to post-war Sweden, back to Poland and then to the new state of Israel, before arriving in Brazil in the early 1950s.
Pereira Lima says: "I jumped into this project with my full heart". He met the family because his Jewish partner's mother is a close friend of Zofia Davidowicz, Joseph's wife. "One day, she heard from Zofia that she wanted to have Joseph's survival story written, but she didn't know how to do it. So my girlfriend's mother told Zofia about me and she commissioned me to write the book".
A private commission of a different sort is My Words I Choose With Care, the writings - in English and Hebrew - of Hava Ish-Horowicz. This memoir has been edited by the writer Amanda Swift, a novelist who usually specialises in children's fiction.
Hava, born in Poland and brought up in pre-state Jerusalem, spent most of her adult life in Manchester where her late husband, Moshe, was the driving force behind the city's Reform synagogue movement. Now 96, she lives today in south London.
One of the couple's five children, Miriam, casually suggested at a family gathering when Hava was 60 that their mother's poems and writings - many of them with a comic touch - might make a good book. "But nothing happened until years later".
Miriam and Amanda Swift often walk together, and they began to discuss the idea of a celebratory book to mark Hava's 90th birthday. The result - with around
100 copies printed - has enchanted family and friends alike, not least because English is, at a minimum, Hava's third or fourth language.
"I spent about a year putting it together", says Swift. "She [Hava] had been to writing classes in Manchester. The book started out as quite a modest venture, but I finished it quite proud of what we'd done."
My Words I Choose With Care is not a narrative memoir like the other publications, but it is still possible to track the arc of Hava's life and how she - like so many Jewish wanderers - adapted to circumstance.
As for Hava, according to her daughter, Miriam, the book has become "almost the only thing she reads". Its publication - like that of the other family stories - has become a validation of a life, a tangible piece of history.