Martha Gellhorn: A Life By Caroline Moorehead CHATTO £20 £18 (+ £2.25 P&P PER ORDER) 0870 800 1122

Martha Gellhorn was a journalist of genius, but Roy Hattersley deplores her reliance on useless men

The ghost of Martha Gellhorn - if it files stories in between heaven and hell - will object profoundly to the description. However, to put her achievement into context, it has to be said that she was the most formidable woman journalist of her day. In one sense she was right to think that her gender was of no more consequence than her chastity - thus relegating it to a very lowly position in her estimation of importance. She was as good as all, and better than most, male foreign correspondents. But part of her importance was the way in which she defied convention and overcame prejudice.

Because she was impatient with the accepted rules, she extended the frontiers of journalism. Martha Gellhorn had no time for "all this objectivity shit". So, when she reported the war in Vietnam, she asked, "Is this an honourable way for a great nation to fight a war, 10,000 miles from its homeland?" Today, nobody would question the right of a reporter to ask that question.

That makes Martha Gellhorn a superb subject for a biography. Caroline Moorehead has seized the opportunity with an élan which her subject would have admired. The result is an adventure story which, true to the genre, has moments of both triumph and tragedy. It does not have a happy ending. Dying of cancer and almost blind, Martha Gellhorn met what her biographer obviously regards as an heroic death. Valedictory messages were written to her many friends. Furniture was labelled to make sure it reached the chosen legatees. Then, wearing "a cream silk nightdress", she took the pill which sent her on what she called "my last travels". As a journalist, Martha Gellhorn was a sensation. As a woman, she was unfulfilled.

Martha Gellhorn was born in 1908, the daughter of the only specialist gynaecologist and obstetrician in St Louis. She was her father's favourite child because she made him laugh. Both her parents were, by the standards of early 20th-century America, radicals. Doctor Gellhorn complained that the pictures Martha brought home from biology classes were less than anatomically explicit. His wife dressed up the little girl as the hope of America's future and took her on the Missouri Votes for Women Parade. Heredity and environment combined to create a woman of cast-iron independence.

Well, almost. In her work she was a foreign correspondent of extraordinary courage, ruthless determination, and estimable self-reliance. But she was also hopelessly dependent on lovers who treated her badly. Caroline Moorehead is unjudgemental about Martha Gellhorn's private life. But observed from any moral perspective - libertarian or conventional - her attitude towards men was pathetic. She did not even enjoy her epic promiscuity. There were two abiding regrets of Martha Gellhorn's life. The failure to write a great book was a disappointment she shared with most other journalists, and the sadness should have been assuaged by the genius of her reporting. The inability ever to have "the kind of close and lasting relationship... that she had seen in her parents" was a tragedy for which she found no consolation.

Heaven knows, she tried. Martha Gellhorn's most famous liaison was marriage to Ernest Hemingway. One day on the way out to dinner, he met a woman whose company he preferred and left his wife standing in the street. For years she tolerated such behaviour. After various brief encounters she became the mistress of Major General James Garvin, the youngest and bravest general in the United States army. The relationship was damaged beyond repair by the discovery that he had spent a night with Marlene Dietrich. She cursed herself for feeling jealous. Her first lover was Bertrand de Jouveral, who as a youth had been seduced by Colette, his stepmother, and then probably became the inspiration for the "hero" of Chéri. The accounts of the celebrity coupling read like the plot of a bad novel.

The affair with Jouvenal resulted in the first of eight abortions - a record made all the more extraordinary by the fact that in early middle age she adopted an Italian foundling. The temptation to suggest that while one termination may be a mistake, eight looks like sheer carelessness is irresistible. Caroline Moorehead never suggests that it was the failure to find love or even much sexual satisfaction (rather than an innately restless character) that made Martha Gellhorn look for fulfilment in her work.

Martha Gellhorn decided to become a journalist long before she realised that her private life was a mess. After Bryn Mawr, which she did not enjoy, her confidence was boosted by placing a couple of articles in New Republic and, aged 21, she became what amounted to a local reporter on The Albany Times Union. But it was Europe and war which attracted her. In the best traditions of literary America, she made her way to Paris - Hemingway's "moveable feast" which, as he predicted, was always in her heart.

It was in Spain during the Civil War that she made her name. For part of the time, Ernest Hemingway was her guide. During her second visit she told him: "I thought I knew everything about war. But what I didn't know was that your friends get killed." Whatever there was left to learn she taught herself in Europe between 1943 and 1945. She almost missed the Normandy invasion when Hemingway, out of spite and jealousy, accepted the assignment with Collier's Magazine which she had coveted. But she booked a berth on a Norwegian tramp steamer, crossed the Atlantic, stowed away on a hospital ship and arrived at Omaha Beach just in time to see "the greatest naval traffic jam in history" putting the troops ashore.

The indomitability which made her first invasion despatch possible is far more typical of Gellhorn's journalism than the occasional arresting phrase. Fine style was not her forte. Her real talent was for being there - at the liberation of Paris, at the opening of Dachau, at the Nuremberg trials, at the Palestine Refugee Camps, at the McCarthy un-American activity hearings. Combined with her romantic radicalism - she predicted that the Republicans would win in Spain because they had an "unlimited supply of guts" - determination to be on the spot made her the near-perfect foreign correspondent. Caroline Moorehead's prose is incomparably better. Unlike some Gellhorn despatches, the biography has both style and substance.

A picturesque account of so complex a character as Martha Gellhorn would be unintelligible were it not well written. Caroline Moorehead meets the need without apparent difficulty. She also displays a superb sense of what is important. The long account of the voyage in an open boat across the Caribbean - searching for a German submarine which she did not find - reveals the quintessential character of Gellhorn journalism. Perhaps the biography is too admiring of Gellhorn, the woman who wore crisp white blouses in the front line and looked good in Marks and Spencer's skirts. But the crucial female message is always clear. A woman of talent and courage can do almost anything that a man can do. But she may have to pay a high price for her achievement.