I’ve often wondered why the obituaries in the Economist are so good. Now, thanks to a terrific piece by Isabelle Fraser I know: they’re written by a brilliant writer, Anne Wroe.

The subject of the week’s obituary is decided on Monday, and it must be written and polished by Tuesday. This 36-hour window is a marathon attempt to consume as much information as possible. “I just sort of feed it all in. Make a huge great collage in my mind. And then it compresses down terribly: there must be millions of words in there and it just comes down to a thousand.”

Often, Wroe is stepping inside the mind of someone who was utterly obsessive about something, and briefly, their passion must become of great importance to her as well. “There was one man I wrote about who was a carpenter, and he specialized in making drawers. It’s quite difficult to get drawers to go in and out smoothly, and you can understand how that could become an obsession. So I had to learn how to make them as well, and find out which woods were best. I had to be just as enthusiastic about how to do it as he was.”

“I think the hardest one was when I did Ingmar Bergman,” she says. “I had to spend the whole night watching the movies, and by the end I was suicidal. They were so dark, and they were getting darker and darker.” She compares it to an Oxford tutorial essay, a kind of fast-paced cramming. “The writers are horrifying; I absolutely dread it when the writers die. There’s such a lot to read!”

Wroe insists on only reading source material by her subject. “I never go to any books written by anybody else. I go to the words on the paper, their diaries. I think it’s the only way to do it, because that’s the voice that has disappeared.”