In May 1954, Robert Capa lost his life when he stepped on a land mine in Vietnam. Magnum lost a founding member, Life magazine lost its first war correspondent, and the world lost a great humanitarian and one of its greatest exponents of photography. He was 40 and just reaching the zenith of his career.

Born Andre Friedmann, the son of a tailor in Budapest, in 1913, he was driven from his homeland by political oppression at the age of 17. He travelled to Berlin and enrolled at the respected Hochschule fur Politik where he studied journalism. When his parents ran into financial difficulties and were no longer able to support him, he got a job as a photographer's assistant.

Soon he was trusted with assignments of his own and had a page of pictures of Leon Trotsky addressing a rally in Copenhagen published in Der Welt Spiegel. The pictures were credited ''Friedmann-Dagephot''. Andre would have been happy to stay in Berlin and capitalise on his early triumphs, but Hitler's Nazis were on the march and, as a Jew, he felt it was prudent to leave.

He drifted to Paris, which at that time was a safe haven for refugees, artists, and intellectuals fleeing Fascism. The young Friedmann fell in love with Gerda Taro, an attractive young German refugee, who was also a photographer. She helped convince Andre that his pictures would command more money if editors thought they had been taken by a successful American photojournalist, rather than a struggling emigre, so Andre Friedmann became Robert Capa.

Capa made his name in July 1936, when Franco led an army of insurrection against Spain's newly-elected left-wing government and the Spanish Civil War began. Wasting no time, the fearless Capa and the indomitable Gerda flew to Spain on an aircraft chartered by Vu magazine.

One of the first photographers to arrive at the front, armed with small, easily portable cameras and more light-sensitive film, Capa started sending back pictures showing the horrors of war as it had never been seen before. His photographs were full of disaster and death but they were also compassionate, showing the dispossessed and the despair and desolation caused to civilians by the terrible conflict.

On September 25 near Cerro Muriano, Capa pressed his shutter release button on what was to become the most famous and most published picture of his career - a militiaman, arms outflung, rifle in hand, falling at the instant of being shot in the head. First published in Vu then in Life magazine, the picture became world famous and a potent symbol of Republican sacrifice. This picture was regarded by many as the greatest war photograph ever taken. Capa became a celebrity.

Years later the same picture caused the Capa family much anguish as doubts were raised about its authenticity. Why was Capa in front of the soldier? Why was there no sign of a wound? Why was he focused on that particular soldier at that instant? The implications were clear. Was the world's most famous war photograph a fake?

Capa supporters dismissed the idea. In 1966 an amateur historian established that the soldier's name was Frederico Garcia. The sister-in-law of the stricken militiaman saw the picture and recognised Garcia.

She said her husband had returned from the front saying Frederico had been killed. In Madrid, military archives show that Garcia was the only soldier to die at Cerro Muriano on September 5, 1936, the day Capa took his famous picture.

In July 1937, Capa was in Paris between shuttling backwards and forwards to the civil war, when he was devastated by the news that Gerda had been killed. While photographing the Republican offensive west of Madrid, she had hitched a lift on the running board of a staff car which was sideswiped by an out-of-control tank. Gerda was thrown into its path and crushed under the tracks. She died the next day.

Capa was grief-stricken for months and none of the many women who followed Gerda into his affections would ever be so close to him.

After the civil war, Capa joined Life and Ed Thompson, the magazine's cigar-chewing managing editor, often berated him because he could not, as he said, ''understand a goddamn word he said''. Capa joked that he had won his English in a crap game in Shanghai.

Not long after he joined Life, the US immigration authorities caught up with him and he was threatened with deportation. A New York model named Toni Sorel offered to marry him, providing him with the opportunity to stay as the husband of a US citizen. They eloped the following day.

During the Second World War, Capa landed on Omaha Beach on D-Day with the first wave during the bloodiest of the fighting. He took more than 100 photographs before wading back through the surf to struggle aboard a returning landing craft. He sent his films of the bloody conflict back to London from the invasion fleet offshore.

One week later he learned that an over-enthusiastic darkroom assistant had turned the heat up in a drying cabinet to speed the process and melted the emulsion from most of his pictures. Only eight frames survived. Life told Capa at first that seawater had spoiled his pictures, so when he discovered what had really happened he was doubly furious. While expressing his anger, however, he told the editor at Life he would never work for them again if they sacked the assistant responsible.

France, Italy, China, Mexico, Israel, Indo-China - wherever conflict reared its ugly head - Capa could be found. A driven humanitarian, he hated war and the devastation it caused, especially to children. Some of his most poignant and compassionate images are of children and youngsters in both times of war and peace.

Away from the front lines, he was surrounded throughout his life by luminaries. He counted Hemingway, Gary Cooper, Ingrid Bergman, and Picasso among his friends. He was a notorious womaniser and a compulsive gambler who loved life.

Capa's photographs have transcended photojournalism to become icons of our history. They reflect his passionate commitment to improving the human condition as well as his unblinking eye for graphic impact. Capa said: ''If your pictures are not good enough, then you're not close enough.'' He also said: ''Like people and let them know it.''

n A retrospective of Capa's work will be on show in the Scottish National Gallery of Modern Art, Belford Road, Edinburgh, from Saturday to July 12.