Book of a lifetime: The Blue Flower, By Penelope Fitzgerald

Penelope Fitzgerald, whose biography I have just written, began work on her beautiful masterpiece The Blue Flower in 1991. It took her four years, and was published in Britain in 1995, when she was 78, and in the US in 1997, where it won the National Book Critics Circle Award. This made her, not just greatly admired, but internationally acclaimed. But there were to be no more novels and she died in 2000, aged 83.

It is a novel about youth, hope, idealism, and the imagination. But her own story is one of waiting, a late start and a late style. And her writing, though humorous, is often about disappointment and loss. She was a comic novelist with a tragic view of life. She began, in her sixties, by writing novels about her own experiences, and biographies of artists and thinkers she admired. But in her last four great novels she moved away from her own life and recreated, with depth and economy, other, past worlds. Her critics would ask, "How does she do it?" She said she did not like to explain too much, as she felt it insulted the reader.

The Blue Flower imagines the families, history and ideas of late 18th-century provincial Germany, the period in which the philosopher Novalis (Fritz von Hardenberg) was a young man, just when Romanticism was emerging. But it is done with minimal explanation. From the first page, when two young men are walking into the courtyard of a family house on their annual wash-day, with the family's sheets and underclothes falling through the air all round them, we are entirely inside their world and their perceptions.

The Blue Flower is a mysterious short book, as well as a completely realised one. Fritz's family life, his work as a tax collector for the salt mines, his philosophical education, the story of the woman who silently loves him, his romantic passion for the naive Sophie, who dies a cruel death, and the landscape of his everyday life are vividly printed on our minds. But his visionary dream of a blue flower that can never be found haunts the book like a half-remembered tune.

Music is very important to the novel, and it is constructed, boldly, in short scenes, like moments in a dream or songs. The blue flower keeps shifting its meaning. What is its name, Sophie asks him. "He knew it once," Fritz replies. "He was told the name, but he has forgotten it. He would give his life to remember it". Fitzgerald said once that the blue flower is what you want of life. "Even if there's no possibility of reaching it, you must never give up".

Hermione Lee's 'Penelope Fitzgerald: a Life' is published by Chatto & Windus