A few days short of her 88th birthday, the oldest winner of the Nobel Prize herself noted that the world's most important literary gong completes her set of major European awards. "I'm delighted to win them all, " Lessing said at her home in West Hampstead, London. "It's a royal flush."

It took Lessing years of struggle and experiment to collect her winning hand.

Her parents, an invalid bank clerk and a nurse, moved from (then) Persia to Southern Rhodesia in 1925 to farm maize. The African upbringing is explored in her 1950 debut The Grass in Singing and through her semiautobiographical Children of Violence series (1952-1969) introduced her to abiding themes of private anguish and social injustice . . . and the links between the two.

Shaped both by avid childhood reading, from Dickens and Dostoyevsky to DH Lawrence, and her father's bitter tales of the First World War, she dropped out of school and joined left-wing circles in colonial Salisbury.

Married at 19, she had two children but left them and her first husband, Frank Wisdom; she later married a Communist colleague, Gottfried Lessing, with whom she had another child. Mother and son moved to London in 1949.

Lessing moved through and out of Marxist militancy, an engagement charted through her heroine Martha Quest in novels such as A Ripple from the Storm (1958). Writer and poet Helen Dunmore recommends them as "a long and complex journey with the character, but also with the author".

Meanwhile, fictional depictions of the colonial racism in Lessing's own background led to her being banned from Rhodesia and South Africa as a "prohibited alien".

Then, in 1962, The Golden Notebook thrust her into the front line of the nascent feminist movement. The novel presents its tormented heroine Anna Wulf as a woman driven towards insanity by the contradictory pressures of her role. To the writer Sarah Dunant, the novel is "such an incredible evocation of the madness as well as the power of creativity. She simply went somewhere where I had never been before, and with a fierce, unflinching intelligence."

The interaction of social turmoil and personal suffering drove Lessing's major novels of the 1970s: Briefing for a Descent into Hell, The Summer Before the Dark, and Memoirs of a Survivor, loved for "first-person, down-on-the-ground human sympathy" not always found in Lessing's other work. Then, to the consternation of many admirers, the imagination already evident in these books pushed Lessing into a fivevolume science-fiction: Canopus in Argus (1979-1983). Other feminist novelists . . . from Margaret Atwood to Jeanette Winterson . . . would later follow, while Lessing's turn towards fable also expressed her immersion in Sufi mysticism. Yet at the time she partly lost one readership without firmly locating another one. She had been a feminist goddess but when she went extra-terrestrial, her admirers didn't know where to look. The science-fiction novels observe human folly from a distance that led disciples to fear that she had abandoned them when, as Dunant remembers, "we seemed to be fighting a lot of battles here on earth".

In any case, Lessing did come back to earth. She published The Diary of a Good Neighbour under the pseudonym of Jane Somers, to experience the condescension meted out to newcomers. "It was interesting to be a beginning writer again because I found how patronising reviewers can be, " she said. Then, with The Good Terrorist in 1985, she roared back into the mainstream with a novel of chaotic revolutionaries and the woman who serves their cause.

Fiercely individual, impatient of all labels and categories, Lessing has always gone her own way. Despite her renown as a pioneer of women's fiction, she later broke ranks with "selfindulgent" feminism, just as she had with Communism. This empathy with the outsider refused all prescriptive limits. Her semi-allegorical novel The Fifth Child (1988) and its sequel, Ben, In The World, focus on a disturbed boy, an alien in his family, and his painful journey towards a kind of peace. The plight of children, and an increasingly 'green' concern with the fate of the earth, fused in the futuristic African landscapes of her epic 1999 novel Mara and Dann, and its 2005 sequel.

Earlier this year, Lessing also published a passionate introduction to the Penguin Classics edition of Lady Chatterley's Lover. She wrote in defence of the writer demonised by many of the very feminists who once lionised her: D H Lawrence. "What we do have from him, " she argues, "is a report on the sex war of his time, and no one has done it better." Except, perhaps, Doris Lessing in her time.