Usually Fitzsimmons celebrates and applauds - great men, remarkable, uplifting events - James Cook, Ned Kelly, Charles Kingsford-Smith and great and successful Australian battles, Gallipoli, Kokoda, Villers-Bretonneux. His many readers feel better - about our country, about our story - after reading a FitzSimons yarn.

But not Breaker Morant. This is a dark, black book about grievous moral failure, about a wrongly conceived and dreadful, appalling war, and about the destruction of a society and its people. Before it was over, there were 115 000 Boers, mostly women and children, in concentration camps, terribly housed, barely fed, diseased and dying in awful numbers.

FitzSimons can find little good in Harry Harbord Morant, the "Breaker". Morant lies as easily as he tells the time, consistently and always. He has several versions of his family background and education, all of them untrue. He takes people's money, their wives and anything they hold precious.

He marauds and drinks his way through Queensland, New South Wales and South Australia. He is a wonderful horseman, an entertainer and a popular versifier but there is more to him than that. He is also a murderer.

Convicted of the murder of 12 people and shot by firing squad, it is certain that Morant's tally of death was greater. One was a much-loved missionary, most were unarmed Boer prisoners.

He treated the prisoners well, he claimed, until the Boers tortured, murdered and mutilated the body of his good friend, Captain Percy Hunt. The Boers did no such thing. Hunt was killed attacking a heavily defended house. His body was untouched apart from the bullet wound to his heart.

There is much more to this book than an account of this one evil man. FitzSimons finds the entire war a terrible catastrophe. Lord Kitchener, the man in overall command, invented the idea of the concentration camps and the destruction of farm houses and farms. He creates a desert where once farming thrived.

A cold, charmless man, Kitchener was also adept at picking precisely the wrong person for the job and backing him to the hilt. FitzSimons argues Kitchener was prepared to win the war by the total annihilation of the Boer population and society. Eventually those in power in London could not allow this to happen.

There are others too, perhaps none more despicable, calculating and murderous than Captain Alfred Taylor, manipulating lesser soldiers like Captain Hunt and Morant.

Though placed before a court martial alongside Morant, Handcock and Whitten, Taylor's cool, incisive mind saw him convincing the court martial of his innocence of all charges.

Taylor saw out his life on his farm in Rhodesia, unpunished and dying, in his bed, at the age of 79. In FitzSimons' view he was "the most guilty, the one most responsible for the many atrocities that occurred".

It will dawn on the reader slowly that this is a book for our times. If some Australians fighting in Afghanistan have been validly accused of war crimes, the Australian government will need to respond to this. Peter FitzSimons has written a book about war crimes in a different country and in a different war.

Make no mistake though, this is a book about a variety of revolting war crimes and crimes against humanity.

There is some light, however, in this bleak, black account of the war. FitzSimons writes in his characteristic way - a style not to everyone's taste - but, for the most part, graphic, engaging and highly readable.

He also finds an action to celebrate with determined, hard-working, successful and brave Australian soldiers to applaud to the full. This is his account of the Battle of Elands River, where a small number of Australians held off an overwhelming Boer force for several days, holding a vital post.

He tells of the bravery and determination of Queenslander Lieutenant James Annat, "a very popular if quietly spoken officer in his mid-thirties" - "as game a man as ever lived", one of his soldiers wrote admiringly to his family. There is not very much else in this book to celebrate.

Breaker Morant marks an evolution in Peter Fitzsimons' work as a writer. It is an important book, powerful in its grim telling, requiring the reader to think carefully and weigh up the moral conundrums FitzSimons exposes.

Breaker Morant may well be Peter FitzSimons best book so far. It deserves a wide and thoughtful readership.