A biography’s a memoir—a portrait from memory of an entire life. One thing that writing life-stories has taught me is that you can’t take your memories for granted. I don’t mean you can’t trust them—you have no choice but to trust them—but you need an open mind.

Liz Phelps is a professor of psychology and neural science at New York University. In this video she describes how memories of emotional events are usually about 50% accurate. The data leaves her without any professional doubt, and yet she admits to feeling (just like the rest of us) that her own memories are absolutely right.

I have an 85-year old client whose long-term memory is phenomenal, but short-term is shaky. He doesn’t just forget and repeat—he modifies too. I now have several accounts of some episodes, and they don’t all mesh. When I’m not sure what my client actually did, I ask, “What might he have done?”

Anyone who’s never written a book would be overwhelmed. I expect it. My job is to bring order to chaos. I actually love it, but I need tools, and mindfulness is my Swiss Army knife. I focus on the character of the person and accept the ambiguity of memory. When my client’s in story-telling mode I don’t interrupt, correct or even ask questions. I’m more interested in moods and motives. I wait patiently for the long and windy first draft.

The more you listen, the more that 50% figure makes sense. Retrieval’s not just a replay button. Memories are taken out and then re-encoded with modifications. Phelps says, “Memories are vulnerable even long after they’re stored, and you can make them vulnerable again by retrieving them.”

Lots of modification tells you there’s lots of emotion. My client really wants to get all the facts straight, and get all the facts in. Meanwhile, details change. He knows we’ll make cuts but wants to start with the full record. I respect that and appreciate it because it’s going to make the book solid—but I want him to enjoy this whole process, not be stressed by it.

However, I understand. The first draft of my bio was three times the length of the final edition. I had to write down everything before I could see what was important. Sharing my story with him helps him worry less.

This is ghostwriting. The ‘ghost’ part means you get into your client’s head and heart. Or, if you’re writing your own story, you reinhabit all those different versions of you. It’s not easy at all, but if you’re a natural-born writer that’ll be what you love most about this whole process.

All this leads to an extraordinary bond. You start with a legal contract and you end up entrusted with the life story of another human being. You become friends, to say the least. I’ve cultivated so many relationships writing people’s stories, and there’s nothing casual about any of them.