“IS MUSIC such a serious business?” So asked Franz Joseph, the Austrian emperor, at the end of the 19th century after a performance of new music in Vienna. “I always thought”, he continued, “it was meant to make people happy.”

Contrary to expectation, interest in classical music (the happy or serious kind) may be on the up. A recent YouGov poll optimistically found that, in Britain, those under 25 were as keen to learn about it as those over 55. In China, between 30m and 100m children are learning to play the piano or the violin. The Sichuan Conservatory in Chengdu alone is said to have more than 14,000 students.

However, classical music composed during the 20th century still has a reputation for being too difficult, too serious and too perplexing. Experimenting with atonality, microtonality, electronic distortion of sound and the role of chance: the developments favoured by the more innovative 20th-century composers do not make for easy listening. In concert-hall programmes and orchestral schedules in Britain and America works by Arnold Schoenberg, Bernd Alois Zimmermann and Gyorgy Ligeti are almost always sandwiched between better-known and loved pieces by Beethoven or Brahms. It is as if an evening of 20th-century composition, even by a famous name, still needs its spoonful of sugar.

“The Rest is Noise”, a year-long festival that is due to start on January 19th at London’s Southbank Centre, hopes to change all that. Inspired by the 2007 book of the same name by Alex Ross, a music critic at the New Yorker, more than 250 events and 100 concerts—starting with Richard Strauss’s opera “Salome” (pictured), and finishing with “El Niño”, an oratorio by a contemporary American composer, John Adams—will trace the arc of music composed in the 20th century.

Academics, curators, theatre directors, composers and writers are all giving talks on related topics: the invention of the production line, the influence of jazz on classical music, and Albert Einstein’s theory of relativity. Over the course of the year 18 orchestras will perform and the London Philharmonic, the leading orchestral partner, has dedicated its 2013 season exclusively to music that was written in the 1900s.

It is an audacious move. As Jude Kelly, artistic director of the Southbank Centre explains, concert series are usually held around “the journey of a composer’s life, or how they may have taken their references from a previous composer.” This is the first to do so through the “march of history”, grappling with how music was coloured by, say, Weimar Berlin or 1920s Paris, the two world wars or by the New Deal in America in the 1930s. It is a way, says Ms Kelly, of “giving context to classical music, which has so often talked about itself in relation to itself.”

Those familiar with Mr Ross’s book will not be surprised that it has inspired a festival. “The Rest is Noise”, which was nominated for a Pulitzer prize, always seemed bigger than its parts, even as it skilfully condensed the history of the 20th century through its music. The original manuscript had to be cut in half, and the book was eventually accompanied by a website, where visitors could listen to selected tracks and read more of Mr Ross’s essays. And although Mr Ross’s gift as a critic lies in his ability to write about music so lucidly that you can almost hear it, this festival will bring to life his belief, as he writes in the book, that “unlike a novel or a painting, a score gives up its full meaning only when it is performed in front of an audience.”

Specialist festivals apart, however, it is still unusual to have a concert series solely dedicated to modern music. Vladimir Jurowski, the principal conductor of the London Philharmonic, admits that the Southbank festival will offer “a much more austere menu” than is usually common, something that may not appeal to everyone—at least at first.

Mr Ross senses increasing openness to the modern repertoire, but “it depends on where you are”. That is as true of New York as it is of London or Berlin. At the New York Philharmonic or the Metropolitan, he feels “a sense from the audience around me that there’s an old automatic…bigoted and prejudicial response to this music…It is a very frustrating attitude; people have grown up with it, and it can be devilishly hard to persuade them to evolve away from it.”

Ms Kelly is confident that the festival will go some way to persuade reluctant listeners. “Audiences who are interested in geopolitics, the history of the 20th century, the economic situation [can find] a route via these things, for them to care who Bela Bartok was.” Mr Jurowski is even more confident of the enlightened attitude of his audience. “My next aspiration would be to do a year that consists solely of music written in the 21st century. But I would need somebody else to write a new book first.”