For some time now, David Grossman has been describing his writing as a means of survival, as a way of no longer feeling a victim in the "disaster zone" of the seemingly eternal conflict that is Israel-Palestine. At moments he has talked of the risk of dispassion, of being paralysed with fear and despair. With the publication of this extraordinary, impassioned novel, such purpose or hope acquires a new meaning and intensity. It now seems that the life to be saved by writing, even though the struggle may be doomed, could only be – perhaps always has been – the life of a child.

To the End of the Land tells the story of Ora, who leaves her home in Jerusalem to walk across Israel to Galilee, in order to avoid the "notifiers" who might arrive at any moment to inform her of the death of her son. It is the trip they had planned together to celebrate his discharge from military service. Instead, he volunteers to rejoin the army in a high-intensity offensive – "a kick-ass operation" – against the Palestinians at the start of the second intifada. Ofer has been lost to his mother "forever from the moment he was nationalised". Her husband, Ilan, has left her, taking her other son, Adam, with him to South America, after she failed to support Ofer when he was investigated over an incident in Hebron which left a Palestinian trapped in a meat-locker for two days. Ora is, among many other things, her son's failed conscience, a voice of caution for him and for her country which neither wishes to hear. Her love for him is limitless, but when he justifies the recourse to violence against the Palestinians, her sole focus is on saving "her child from the barbarian standing opposite her".

Grossman has not ventured into this territory in his fiction for a long time – not since his earliest novel, The Smile of the Lamb, which was the first Israeli novel to be written about the occupation. To the End of the Land is a chronicle that loops back through Ora's memory and history to cover every war since the founding of Israel in 1948. Ora believes that Israel has no future: "It doesn't really have a chance, this country. It just doesn't." Although Ora will never leave Israel, she is running away (the Hebrew title is A Woman Escaping News). All the characters in this story are in some sense escapees. The novel is a tribute to their resilience as well as to the precarious vitality of family life, memories of which form the densest fabric of the book. Nonetheless, To the End of the Land offers its own bleak reply to the prayer that ends See Under: Love, the most famous of Grossman's novels: that a man might "live in this world from birth to death and know nothing of war".

Ora takes off on her journey in the company of Avram, the man who is in fact Ofer's biological father, narrating her son's life, from birth to what may or may not be death, as they travel across the land. The complex erotics of their story, and of the love-triangle between Ora, Avram and Ilan, is one of the strongest aspects of the book; as is the deft precision of Grossman's depiction of the land – beautifully rendered in Jessica Cohen's translation – that veers, along with the rise and fall of Ora's moods, from lush to desolate. Ora is, as she puts it, the first "notification-refusenik". Ofer will not die as long as she keeps talking and writing about his life (she keeps notebooks as she goes). "Though I walk through the valley of the shadow of death," Avram whispers to her near the end of the novel, "I will fear no evil, for my story is with me." She also believes, in what she herself recognises as "flipped-out" magical thinking, that if she is not there to receive the notification, then it will be impossible for her son to have died. Although he has often and brilliantly performed such feats of ventriloquism before, it is of special significance that Grossman has taken the risk of telling this tale through the eyes of a woman. Before anything else, To the End of the Land is a novel that recounts like no other I have read the lengths to which a mother will go to preserve the life of her child.

In his literary essays, Grossman has described how dispersing himself through his fictional characters allows him to hold on – just – to the fragments of being that would otherwise cause him to fall apart (characters like Ora, at once steely and endlessly changeable, become then a microcosm of his art). It is for Grossman the ethical gift of fiction, working against our natural impulse to protect ourselves "from any Other", to force writer and reader into another person's skin. This has political consequences: "I write and I try not to shield myself from the legitimacy and suffering of my enemy," he states in his 2007 Arthur Miller Freedom to Write lecture, "or from the tragedy and complexity of his life, or from his mistakes and crimes, or from knowing what I myself am doing to him." Grossman has been one of the most outspoken Jewish Israeli voices against the occupation. He demonstrates weekly against the house demolitions in the East Jerusalem neighbourhood of Sheikh Jarrah (and was beaten by the police a matter of weeks ago). He has always been scrupulous in avoiding what he calls in the same 2007 essay the "public, general, nationalised idiom". It is because Anshel Wasserman, the writer who miraculously returns from the concentration camps in See Under: Love, had no "Jewish nationalism" in his stories that – like Grossman, one could say – he found "favour with the children of the world".

And yet, this is a novel that forces us to ask more than ever: who are the Arabs for Israel's Jews? When Ora gets the Palestinian-Israeli Sami to drive her and Ofer to his military registration point, it is the son who points out the crass insensitivity of what she has done. Later, in one of the most powerful scenes in the novel, Sami allows her partially to redeem herself by driving her through a checkpoint with a sick Palestinian child in her lap to a makeshift hospital where she, and we as readers, are witness to the precariousness of life under occupation (a child on the other side against whom all the odds are stacked but who deserves no less to survive). Sickness is the great equaliser, and it is everywhere – Ora, Avram and Ilan first meet as hospital patients in the midst of the 1967 war. However, the most brutal scene is Avram's memory of being tortured by the Egyptians in the 1973 war. It is the core trauma of the novel and Ofer is its child – he is conceived when Ora determines to prove to Avram that his experience has not unmanned him. As Avram digs his own grave and is buried alive, mocking Egyptian soldiers take photographs. Reading this moment, it felt as if Abu Ghraib – the signature atrocity of the west – had been handed over to the Arabs. In this novel, anyone is capable of being a monster, but it is the Israelis who suffer most.

To the End of the Land emerges at a time when, by Grossman's own account, it has become harder and harder to resist the dominant narrative of his country, a narrative he has done more than most Israeli writers to expose. Ora is by no means immune from it. When Ofer is frightened as a child by what he sees as too few Jews in a country fenced in by enemies, she takes him to the Armoured Corps site at Latrun and shows him the tanks and guns: "What was good enough for a whole country was good enough for my child." The "public, nationalised" narrative which Grossman has so scrupulously avoided till now makes its appearance like the return of the repressed.

It has become part of the legend of this novel that, while he was writing it, Grossman's son Uri was killed on the last day of the 2006 Israeli offensive in Lebanon. It will never be read now without that knowledge, without that unspeakable pain, which is in danger of conferring on the book a mythical status. To the End of the Land is without question one of the most powerful and moving novels I have read. But we do the novel, and Grossman, no favours if we turn it into a sacred object, beyond critical scrutiny and outside the reach of the history to which it so complexly and sometimes disturbingly relates.