Rahel Varnhagenthe WildfireENFP

One evening in March 1810, Rahel Levin sat down in Berlin to write to her friend Pauline Wiesel, who was far away. She was 38. She greeted Pauline twice over, as beloved friend in the woman's word and the man's, as if one word could not hold her.

The letter was a torrent. Her wounded heart wept, she wrote, because their lives were running away without their living them together.

To see why it mattered, you have to know who the two women were.

Rahel was born in Berlin on 19 May 1771 into a wealthy Jewish family. What she did, more than anything, was gather people. In the family house on the Jägerstraße she kept a salon where writers, thinkers and aristocrats came to talk. It had no office and no rank. It ran on her warmth, her wit and her readiness to let anyone interesting in.

And she wrote letters, endlessly. Some six thousand of them survive. That is a Wildfire at full strength: the center of the web, everyone's correspondent, always a little behind.

Pauline was something else. She had loved a prince, Louis Ferdinand of Prussia, openly, and Berlin society never accepted her. After he was killed in battle in 1806, she could barely keep a place in the city.

In that letter Rahel told her why they belonged together. The two of them, she wrote, stood beside human society, with no place, no office and no title waiting for either. A Jewish woman in Prussian Berlin, however brilliant her salon, had none. Neither did a woman who had loved a prince in the open.

She left her guilt in too. It was a disgrace, she wrote, that she had not written sooner. Wildfires know that guilt well. The bigger the circle, the easier it is to neglect the one person in it who truly sees you, because that person never demands attention the way the others do.

She also knew they were opposites. Rahel was anxious and careful, and often unwell. Pauline was lively and sure of herself. Rahel loved her for what she herself lacked.

In 1814, at 43, Rahel was baptized and married Karl August Varnhagen, a writer fourteen years younger. He became the keeper of her words.

She died in Berlin on 7 March 1833, aged 61. Near the end her husband wrote down what she said. “What a history!” she began. She was a fugitive from Egypt and Palestine, she said, and here she found help, love and care. Then she turned toward the part of herself she had spent decades trying to get out from under.

Varnhagen gathered her letters into a memorial book, Rahel. A century later Hannah Arendt wrote that Rahel was her “closest friend, though she has been dead for some hundred years.”

The woman who wrote to hundreds and felt truly known by very few is now known by readers she never met. It started with letters written in the evening to a friend outside the walls.