One girl, one voice, an entire war.

Anne Frank was given a red-checked diary for her thirteenth birthday, a few weeks before her family disappeared into a hidden annexe above her father's business in Amsterdam to escape the Nazi round-ups. For just over two years she filled it, and in doing so she made herself one of the most widely read writers of the twentieth century, though she did not live to know it.

What is astonishing about the diary is not that it is a document of atrocity, because for long stretches it is not. It is the diary of a teenager. She writes about her irritation with the adults sharing the cramped space, her first love, her frustration with her mother, her ambitions to be a writer, the ordinary storms of becoming a person. The horror is the frame, always pressing in from outside, but the life inside the frame is vividly, recognisably normal.

That is exactly why it works. A statistic of six million is a number the mind cannot hold. Anne Frank is one specific girl, funny and self-aware and difficult and hopeful, and when the diary stops, abruptly, because the annexe was betrayed and she was taken to Bergen-Belsen where she died weeks before liberation, the loss is not abstract. You have come to know her, and then she is gone, and the scale of the larger crime arrives through that single door.

Her father, the only member of the hidden group to survive, spent the rest of his life getting the diary published, against her own stated wish for privacy but in service of a larger one she had written down, to go on living even after her death. She got the wish. The book has been translated into more than seventy languages.

For anyone who doubts that one small, honest voice can matter against overwhelming force, Anne Frank is the answer. She had no power, no platform and almost no time. She wrote the truth of her days, and it outlived the empire that killed her.

Write down what is true about your one small life. You have no idea what it will carry.