Kate Grenville won the Orange Prize in 2001 with her fine novel The Idea of Perfection. We have had to wait five years for The Secret River but the wait has been worth it.

The story begins in early 19th-century London and we are in Dickens territory, with young William Thornhill struggling to bring up a family and maintain a living as a Thames boatman. The moral terrain is also Dickensian, for his survival more or less depends on criminal enterprise, but even petty larceny is mortally dangerous to one of William's class. He is saved from hanging by the devotion of his wife, Sal, and a death sentence is converted into transportation to New South Wales. The pregnant Sal and their son, Willie, are permitted to accompany him on the grim nine-month voyage.

When we reach Australia the story really takes off. From an account of the family's bewildered arrival in a strange and emerging Sydney, the novel grows in conviction and power. As part of his sentence, William is "assigned" for 12 months not to an exploitative "master" and almost inevitable gang labour, but to his wife, a stroke of luck as theirs is an unusually close bond (Sal is the novel's co-hero). Grenville is a writer whom one instinctively trusts, so presumably this is historically founded. Not that it matters, for it prepares us for the novel's major theme -the intimate relationship between power, desire, freedom and responsibility.

Soon the increasingly capable couple contrive to secure, through judicious pilfering of rum from William's employer, a fair level of material comfort. But this time, having learnt his lesson, William acts before nemesis can strike. He leaves Sydney a free man, on a boat with a dubious associate from his London past, to follow the Hawkesbury, the "secret river", and the rumours of land waiting to be claimed.

The land, of course, already has its time-honoured, Aboriginal landlords. Pretty soon, other dodgy newcomers arrive to pit their greed-sharpened wits against the indigenous population. With freedom and power at last in his grasp, William must choose how to act and what, finally, it will mean to be -in both senses of the word -a man.

This is the heart and stomach of the book. In spare, unpretentious prose, Grenville charts the brutal truth that violence breeds violence; that human beings, if done down, will, almost as a necessity, in turn do others down -or be drawn to do so. The tale of William Thornhill and his family is a deeply moral one: adversity is shown both to sharpen and to blunt the moral faculty, with consequences as fatal, in their way, as the hangman's noose.

With some exceptions, Australian fiction can be overlooked here, perhaps because the British feel it is alien or parochial. This is a pity. It has much to teach us, not least about the shadow side of "civilisation" and "the things not spoken of" that flow in the lives of those who made, and were made by, it. Splendidly paced, passionate and disturbing, The Secret River is just such a novel.

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