By Norman Lebrecht

In August 1942, with emaciated corpses littering the streets and German guns booming all night long, Joseph Stalin decided that what Leningrad needed most was to hear the seventh symphony of Dmitri Shostakovich. The thunderous work had been premiered a few months before in Kubyshev, a city in Russia’s interior to which the composer had been evacuated. The symphony had already been heard in Britain and the U.S. in broadcast performances conducted by Henry Wood and Arturo Toscanini. Bring it to Leningrad under German siege would be both an act of defiance and a triumph of propaganda.

The city’s radio orchestra filled out its ranks with music teachers, ex-players and amateurs. The concert, conducted by Karl Eliasberg on Aug. 9 – the day Hitler had designated for Leningrad’s surrender – was beamed at the German army through giant loudspeakers. Hearing the music, a German officer is supposed to have muttered: “We’ll never beat these people.” Although the siege lasted another 18 months, Leningrad held out until the Germans were pushed back.

Roughly 60 years later, Stephen Johnson, a BBC journalist, interviews the clarinet player in that Leningrad performance, Viktor Kozlov, asking him what he felt when he heard the Leningrad symphony today. Kozlov, with his wife alongside him, burst into tears. “It’s not possible to say,” he sobs.

That admission sets Mr. Johnson off on a deeply personal examination of how a work of music can save the lives and minds of those who play and hear it. Mr. Johnson, we learn from his book, suffers from a bipolar condition. He grew up in a dysfunctional family with a depressive father and a violent mother with a severe personality disorder. As a boy, he recalls, “I had to lock myself away to avoid a destabilising mother… if I could have voiced the commandment I unconsciously repeated to myself during that period, it would have been: “I must not feel, I must not feel”.

Music, he says, was the only space he could indulge feeling. In his early teens, Mr. Johnson discovered Shostakovich’s fourth symphony, the one the composer shelved for 125 years after Stalin took against his opera “Lady Macbeth of the Mtsensk District”. Memorising the symphony – and revelling in its “terrifying mood swings” and explicit existential threats – Mr. Johnson ran it though his head as a kind of soundtrack as he cycled home from school. “Living with your mother,” his therapist-wife would volunteer, “must have been like that symphony”.

Shostakovich had composed the fourth symphony during Stalin’s great terror to save his own sanity and to report covertly the mass arrests and murders – achieving, as Mr. Johnson puts it, “a degree or two of distance from the emotions he is articulating”. As Shakespeare writes in Hamlet (which Shostakovich set to music): “though this be madness, yet there is method in’t.” The composer had found a means for making sense of madness. “If Shostakovich could find the method,” thinks the teenage Mr. Johnson, “then perhaps I could too”.

What follows is an intensely readable, highly personal analysis of the major works of a composer who, Mr. Johnson decides, has recorded a collective experience for an all-inclusive listenership. Streaks of black humour in the music relieve the toil of tragedy. A piccolo solo in the eight symphony pinpoints the absurdity of individuality in tragic times. The tenth symphony, written as Stalin lay on his deathbed, contains in its signature theme hints of the composer’s defiance and relief: “I’m still here!”.

When his mother is finally taken to an asylum, Mr. Johnson writes as if he were Shostakovich when Stalin died: “The case against me had collapsed. It could now be seen what I had to contend with all those years. Even I could no longer accuse myself of make-believe.” Anyone who has survived an abusive childhood will recognise this as the moment when redemption seems possible and life can at last be lived.

There is a theory in modern psychology that refers to the “internal totalitarian object”, a device by which the psyche uses an external evil to bludgeon the self into compliance. Such an object lives on in Russians as a sneaky admiration for the mighty Stalin; Mr. Johnson feels both love and awe for his maniacal mother.

“When I look back at the strange ordeal of my early home life,” he writes, reflecting on Shostakovich’s eighth symphony, “I seem to hear this music saying, ‘it is nobody’s fault.’ Blame is one way of giving meaning to life, but it keeps us prisoner.” In the eighth string quartet he hears intimations that the composer is contemplating suicide while somehow throwing a lifeline to Mr. Johnson in the same dark place.

All great music teeters on the edge of madness. This troubled writer makes a convincing case that the music of Dimitri Shostakovich helped to save his mind. In life’s crises, he suggests, each of us comes up against an internal siege of Leningrad and music comes to our relief.