It is, says Norman Lebrecht, a question which has occupied him for half his life. For a short, intense period of time — 100 years or so — a “handful” of people appeared on the public stage “and changed the way we see the world”. Half of them, suggests Lebrecht, were Jews.

In his newest book, Genius and Anxiety, How Jews Changed the World, Lebrecht attempts to provide an answer to his question. “There is no simple rational explanation”, he says, and yet in this massive and fascinating volume, Lebrecht, a music critic and novelist with a 40-year career in journalism behind him, does his best to give the reader the solution.

He does it by dividing the century between 1847 and 1947 into decade-sized nuggets of cherishable information about our genius forebears — many of whom, it must be admitted, had a certain amount of anxiety about being Jewish.

Among Lebrecht’s cast of thousands are the expected and well-known — Freud, Einstein, Trotsky, Kafka, Disraeli — and the less well-known, such as Karl Landsteiner, Paul Ehrlich, or Fritz Haber. And then there are the people most of us have simply never heard of, such as Eliza Davis, a tough Jewish woman who challenged Charles Dickens over his portrayal of Jews in Oliver Twist — and won.

Besides that, Lebrecht adds another layer by telling us a “who knew?” element about the really famous. So we learn, for example, that before the Lubavitcher Rebbe became the Lubavitcher Rebbe, he was working as an engineer in the Brooklyn Navy Yard in New York, and “in lunch breaks he reads Ripley’s Believe It Or Not and Dick Tracy over his workmates’ shoulders”.

For those who think they knew everything about Sigmund Freud, Lebrecht offers the delicious “gotcha” morsel, that Freud forbade his wife Martha from any manifestation of Jewish practice throughout their marriage. But on the Friday night after Freud’s death, Martha lit Shabbat candles — and continued to do so for the rest of her life.

Lebrecht reminds us that the composer Arthur Schoenberg, probably alone among all the Jewish converts to Christianity, “goes to the Liberal synagogue on Rue Copernic [in Paris, when the Nazis seize power] and demands to be readmitted to the Jewish faith that he left in the 1890s… he demands a formal ceremony. On July 24 1933, the synagogue certifies his re-entry into the Community of Israel”.

And just in case this weren’t enough, the cherry on Schoenberg’s cake is that his witnesses were “the painter Marc Chagall and the scientist Dimitri Marianoff, Einstein’s son-in-law.” If you’re going to do it, go big, seems to be the subtext here. (It should perhaps be noted that the synagogue told Schoenberg that re-admission was an entirely bogus ceremony and not necessary, but he insisted).

The indefatigably curious Lebrecht asks the question: why did these Jews, some practising, many not, think “outside the box”?Moreover, he thinks that Jews “managed to see what others could not” precisely because of their upbringing, of their schooling in Talmudic disputation, of their propensity to say “what if?” and push a problem or a situation just one stage further than everyone else.

It’s a bit of a stretch, such a proposition, particularly with the men and women who outright rejected Judaism, but Lebrecht is convincing.

He takes as his starting decade 1847, the year that composer Felix Mendelssohn and his sister Fanny, also a composer, died; the year Karl Marx wrote the Communist Manifesto; and the year that Benjamin Disraeli became the de facto leader of the Tories in Parliament. The book is written in the historic present so that the reader is carried along on an almost breathless stream of name-dropping — but that only serves to give a sense of how Jews everywhere were making the most of the opportunities of 19th century emancipation and enlightenment. New ideas and how to put them into practice were everywhere and Jews, says Lebrecht, were almost always at the forefront of such developments.

The year 1847 is “a breakthrough year in terms of Jewish engagement. And I took 1947 as the endpoint because on the very day that the United Nations is voting on the formation of a Jewish state, is the day when the first Dead Sea Scrolls are brought to Jerusalem. It’s not just history ending and history beginning, but this constant process of re-invigorating history, of re-writing history, because with those scrolls, we now know that our sources are far more diverse than we ever imagined them to be”.

Though Jews were almost ubiquitous with the latest ideas or inventions, Lebrecht says that “without exception” the ideas were always accompanied by a strain of anxiety. “They said, in effect, I’m going to have to put this into practice NOW, because you never know where the next pogrom is coming from”.

His book, he says, “is not just about how Jews changed the world, but about how the world changed the Jews. The Jews of today are unrecognisable from what they were in 1847 — in terms of their civic status, their attitudes and their physicality. Jews changed; and the Jewish religion changed in many ways, even among the most Orthodox.”

Jews, insists Lebrecht, “see the world in a way others don’t.” He offers as an example Karl Landsteiner, the man who “made it safe for us to have major surgery, because he discovered blood groups.” Around 1900, Lebrecht says, surgery was quite advanced, operations were taking place but patients were dying of shock. It was Landsteiner who asked, could it be the blood, and he found three different blood groups straight away. But he was initially derided and it was not until 1907 that another young Jewish doctor in New York decided to try Landsteiner’s discovery, matching a blood type to that of a patient. It worked and ever since patients have been treated with their own specific blood groups.

Admittedly, says Lebrecht, Landsteiner was “such a self-denying Jew — he converted to Christianity — that he once threatened to sue a publisher of an American Jewish directory for including him. And yet, look at the question he asked — when is blood not blood? Is there a possibility of there being more than one type? The Talmud says yes, there is. Cranial blood is different from abdominal blood”. Lebrecht says Landsteiner is unlikely to have been aware of the Talmudic prescription.

“But he knew to ask the question. It’s to do with a Jewish style of discourse”.

Observant readers may have noted that there are not many women in Lebrecht’s catalogue of Jews who changed the world — although we do meet Golda Meir and one of the writer’s favourites, the French Jewish actress Sarah Bernhardt, who, claims Lebrecht, more or less invented the cult of celebrity, by proclaiming herself “so famous that you can’t touch me”.

Along with Lebrecht’s evident and justifiable glee at the arcane stories he has unearthed about his Jewish pantheon of game-changers, there is another level of satisfaction.

His 2002 novel, The Song of Names, has just been made into a feature film starring Tim Roth and Clive Owen and our conversation takes place on Lebrecht’s return from a red-carpet ride at the Toronto Film Festival where the movie premiered.

The book, which won the Whitbread First Novel Prize, is about the friendship between two young boys, Dovidl and Martin. Dovidl’s family are trapped in Poland at the start of the Second World War, Martin’s father is a successful and well-connected musical talent agent. The boys meet when Dovidl, a violin prodigy, comes to study at Martin’s house with a celebrated teacher.

The two boys become very close but on the eve of an international concert debut arranged for him by Martin’s father, Dovidl disappears — and is not seen again for 35 years. As adults the two re-connect — and the mystery of Dovidl’s disappearance is explained.

Lebrecht’s agent received an approach from a film-maker the week after publication but it took a long time in “development purgatory” before the film got off the ground. It is directed by Francois Girard who, says Lebrecht, was assiduous in asking for advice to make sure the film’s details were as authentic as possible.

But there is one huge difference between the book and the film: in the book, both boys are Jewish. In the film, apparently at Tim Roth’s suggestion, Martin and his family are not Jewish. “It nearly killed me”, Lebrecht says. “It works, but I lost a lot of sleep over it”. Still, he did not write the screenplay and was on hand primarily as a consultant and he is very happy with the finished product.

With the publication of Genius and Anxiety and the upcoming release of The Song of Names — which is showing on October 6 at this year’s London Film Festival — Norman Lebrecht feels, he says, “as though all my Chanucahs have come at once”. Then he laughs and says he is returning to his next novel, about his first love, music. So far, he reports, “there are no Jews in it.”

Genius and Anxiety, How Jews Changed the World is published by Oneworld Publications