‘Only those who receive a letter in a bottle can decide whether to be the final recipient. By writing your book you made of each reader a final recipient, a possible somebody somewhere, for the person who one day threw a bottle into the sea.

‘And through this voyage, in spite of, and beyond death, a child continues on his path. And thanks to this letter in a bottle, “rocked by the ocean”, rocked by the written word, it offers to each mother the most beautiful of messages: that of hope, that of life.’

The four of us – the mother and her compagnon, the psychologist and I – went for lunch in the town square. It was one of the earliest days of summer and we happily sat outside where it was pleasant and fresh. As we ate and chatted and my French began to fade in weariness, the town square began to fill up with hundreds of schoolchildren. It was a celebration of the approaching end of the school year, and all the schools in town spilled their children, dressed in matching T-shirts depending on their school and year group, into the town square. The sun came out and began to bake the psychologist and me, while the other two – the mother and her compagnon – sat just under the shade of the awning.

By the end of lunch Olivier’s face and forehead, and my neck and shoulders were an angry red, and in the following weeks the skin would peel off to remind us of a surreal but lovely lunch. As he later wrote: ‘I will never forget the moments of conversation, of reflection with HER, which proved to be one of the precious and lasting gifts that the day offered. And I thank the sun for having engraved this day on my forehead, like a red-hot iron. Yesterday, we had never seen one another, but today and for a long time to come the sun’s seal of recognition was branded onto us.’

Conversation, as far as I could follow it through the din of the children, was wide-ranging, easy and interesting. The mother and I were quiet, emotionally drained by our meeting, but the men were ready to talk and the food was good. I found my attention floating away, and I found myself looking surreptitiously at her.