Where on earth did all this Mahler come from? Half a century ago, the symphonies were a concert hall novelty, performed sparingly to an audience composed of continental émigrés and curiosity seekers. A quarter century back, a Mahler cycle was an epochal event, unlikely to be heard again in a lifetime—or so Claudio Abbado and Klaus Tennstedt vociferously maintained. 

Today, Mahler has displaced Beethoven as the pole around which concert seasons are planned. In the coming year, London’s South Bank—Europe’s biggest arts centre—will stage no fewer than 27 performances. China and Australia will hear their first complete cycles. South Korea has organised a cycle, by no means its first. The BBC Proms has more Mahler than ever before. Even if it weren’t a centennial year, orchestras would still be playing Mahler. His is practically the only name in the symphonic canon that sells the house within days of going up on the billboards.

And it’s not just live performance. Over the past 15 years, while the record industry has withered, the number of Mahler recordings has doubled, to a total of almost 2,000. Bearing in mind that he only wrote 11 symphonies and six sets of songs, that makes an average 100 discs for every single score with Mahler’s name on it.

Mahler’s music has been featured in 47 movies, starting with Luchino Visconti’s Death in Venice back in 1971. Hollywood has hard-wired him into the soundtrack lexicon; every time Harry Potter achieves liftoff on his broom, you catch a snatch of Mahler’s Resurrection.

He is played at state funerals and church weddings, at political summits and atheistic convocations. More than any of his coevals—more than Strauss or Sibelius, Puccini or Rachmaninov, Elgar or Stravinsky—Mahler’s is the music of our millennial times.

Why Mahler? Why did this half-forgotten composer rise from the grave to chime with a distant future? Alive, Mahler was mocked, misunderstood, racially abused and generally regarded as an inept composer who could not or would not deliver the satisfactions expected by a paying audience.

None of his works played by the rules. Sonata form was distended into five or six movements. The orchestra leader was made to lay down his precious violin in the fourth symphony and screech a full tone higher on a gypsy fiddle. Left and right of the orchestra went out of phase in the 10th symphony, like tectonic plates shifting beneath the audience’s seats. It is easy to see how Mahler provoked discomfort and outrage in 1910. ‘My time will come,’ he proclaimed, with uncanny prescience.

I have spent half my life studying the Mahler phenomenon, searching for its causes. At first impression, it struck me that Mahler was dealing with issues I could recognize: racism, workplace chaos, social conflict, relationship breakdown, alienation, depression and the corrosive consequences of self-inflicted stress. He seemed far more relevant to my joys and anguish than the imperial bluff of the Enigma Variations.

And nothing he did conformed to first impression. Self-contradiction was everywhere. After his earliest scratchings he never wrote for less than full orchestra, often with voices and on one occasion rising to 1,000 performers. Yet the forces that he amassed expressed emotional intimacies that are seldom whispered outside the marriage bed or the consulting room. Message seemed to be at war with medium.

Every phrase he wrote was susceptible to more than one meaning. His most important innovation, musical irony, allowed Mahler to get away with voicing social criticism that could have cost him his job. Later, and elsewhere, the same ambiguous device allowed Dmitri Shostakovich to describe the horrors of life under Stalin. Mahler enabled music to function as political commentary.

But that was not his main purpose. Like Sigmund Freud, whom he consulted in distress during a summer of marital breakdown, Mahler used his own life as a template for everything he wrote and ultimately as a means of understanding the human condition. His music is simultaneously text and exegesis, sensual seduction and intellectual challenge, always and above all an urge to heal the world.

Scholars who try to analyze Mahler through the prism of his forebears, Bruckner and Brahms, or of his followers Schoenberg and Shostakovich, come crashing against the rock of his originality. Never easily categorised, he held himself apart from the conventions of his craft and the little boxes that wiki-people like to tick.

'I am three times homeless', he declared, defining not only his exclusion as a Jew but the externality of his music, his outsider’s perspective. Mahler, with the gypsy fiddle, ushered the unmentionable into the middle-class concert hall. In the sixth symphony, he was Jeremiah, warning that the city would fall if it did not repent its sins—as indeed it did in the First World War, soon after his death.

These perceptions and ambitions ran far beyond the norm for a symphonic composer. And when Mahler in his three last symphonies contemplated his own battle with poor health and a failing marriage, there was a quality of self-observation seldom seen outside the laboratories of pioneering science. This, for me, is Mahler’s compelling attraction: his blinding faith that, through music, we can make sense of our world.

And make sense, even more cogently, of our private lives. Mahler communicates one on one. Among 3,000 other listeners at a concert, you are always alone with Mahler. I have seen people with tears trickling unawares down either side of their nose. I have known some whose lives have been redeemed by a Mahler experience. With Mahler, it is always personal, always him and you.

From the funeral march that is revealed as a nursery rhyme in the first symphony to the ‘catastrophe chord’ of the tenth symphony, he flourishes a kaleidoscope of parallel narratives and conflicting agendas that are all too familiar to the 21st century citizen, struggling with a life-work balance in an accelerating twitter of attention-seeking technologies. The more complicated life becomes, the more I need Mahler to help separate the strands into the root priorities of love and truth.

Everyone has their own 'why Mahler' answer—even if it's just 'why not?' But his unstoppable rise over half a century suggests that Mahler has tapped into an acute need in a fast-changing world, a hole in the heart of our existence. I would not know what to say if Beethoven came knocking at my door, let alone Mozart or Bach. But if Mahler turned up unannounced you would know exactly who he was and why he was there. He is the composer of our lives.