Menuhin's parents Moshe and Marutha, as young immigrants to the US from, respectively, Palestine and Russia, had been looking for an apartment in New York; a prospective landlady, pre-judging Marutha by her blonde hair and blue eyes, offered to rent to them because she thought they were not Jewish. "My grandmother was outraged," says Zamira, "and she decided at once that if they had a son he would be called Yehudi."
He was a true child prodigy. In his early recordings, made when he was about 12, he plays with the sophistication and insight of a mature musician. Stories are legion of his parents' determination for him to succeed.
Zamira points out a timetable in the exhibition: "It leaves little room for anything except practice, sleep, eating and rest," she says. "But theirs was such a different world. What do you do with a child like that? A son who says he wants to study the violin and stamps on the tin instrument someone gave him for his birthday, and who then performs pieces after one year of study that most others would play after six years?"
Despite the intense schedule, she insists, "he had a very happy childhood. He was sheltered by his parents, who decided everything for him up until the time he married my mother. They kept him from believing he was a celebrity. He did know that everybody spoke of him, but I don't think he read newspapers. He was happy making music."
Menuhin also married young, aged only 22; his first wife was Nola Nicholas, the daughter of an Australian industrialist. The couple had two children, Zamira and her brother Krov. "It was a marriage of love and attraction, but between people who really didn't have enough in common," Zamira reflects, for the marriage ended in a painful divorce. Subsequently, Menuhin married the dancer and actress Diana Gould, with whom he had two sons, Gerard and Jeremy.
During the Second World War, Menuhin performed for the departing troops, something he found moving and traumatic - but more devastating still was the experience of performing (with the composer Benjamin Britten at the piano) for survivors of the Belsen concentration camp after its liberation.
It seems that he had not been remotely prepared for what he might find there. "He was a very young man with a golden history until then and it must have been pretty galling," says Zamira. "An agitator came from among the survivors and brought others with him whom he had managed to convince that my father was a traitor: they declared that what Yehudi Menuhin doesn't understand is the ethics of playing for anyone who was in the concentration camps.
"He talked to my father and made his opinion only too clear. My father did apologise; he said it was true that he had not suffered himself and that he should probably have been more sensitive to what these people were feeling. The man came to his hotel the next day and apologised, which was wonderful. Finally they both understood each other better." How did the experience affect her father? "I think he grew up," she says.
When the Nazis came to power in 1933, Menuhin, who was then still a teenager, was among the first Jewish musicians to declare that he would not perform in Hitler's Germany. After the Third Reich's defeat, he was also the first to return, determined not to prolong the enmity. He often took long-term, magnanimous views of difficult situations. Zamira agrees that his sheltered upbringing may have given him the detachment for that vision to take shape:
"He had a firm belief that music would overcome all kinds of problems, and I think he was a bit disappointed sometimes. But he was not a man who could hate."
Menuhin discovered yoga in the 1950s and practised it for the rest of his life; together with this went his preoccupation with wholesome food. Sugar was the enemy. Zamira recalls that "if we received sweets at a party, he was so cross that he'd wind down the car window and throw them into the street!"
He would be constantly away on tour but, Zamira says, the family always spent three weeks together in the summer, often in Gstaad, Switzerland, where Menuhin founded a star-studded music festival that still takes place each year. Later, he found time to serve as president of the Jewish Music Institute, in conjunction with which the Menuhin Competition is being held, among other centenary events.
Many of Menuhin's projects have been wide-reaching, but Live Music Now, in particular, has been a vital force in proving music's capacity to offer comfort and spiritual sustenance, in settings from hospices to prisons to primary schools.
As Zamira says: "People are beginning to realise, finally, how important music is for everyone." And, with the latest Menuhin Competition gearing up for its gala weekend next Saturday and Sunday at the Royal Festival Hall, Menuhin's legacy is being brought to a whole new generation of young musicians.
Live Music Now: A Celebration of Yehudi Menuhin takes place on Sunday April 17
The Menuhin Century on Warner Classics marks the 100th anniversary of his birth on 22 April. It is comprised of 80 CDs, 11 DVDs and a hardback book, and draws on the 70-year relationship between Menuhin and the record company HMV/EMI. It was released on April 1.
