In The Lost City of Z (Reviews, Oct. 13), David Grann travels to Brazil to retrace British explorer Percy Fawcett’s fatal last mission in the 1920s.

Your wife appears throughout the book. What was her reaction to your growing obsession with Fawcett and the quest to find Z?

She has a good sense of humor, which is always helpful, since I tend to get a little bit obsessive. In many ways, she’s the sensible one, though, and she really helps me think things through. She understands me, yet makes sure I have at least one foot on the ground before I do something stupid.

How does a nonadventurer with poor eyesight and a terrible sense of direction, like you, survive the Amazon?

The honest answer is that I don’t often fully think about what I’m doing—I think much more about what I’m trying to get done and what I want to know. This story in particular is so compelling to me that my desire to try to understand what motivated Fawcett is what got me going.

Was it always your intent to have yourself involved in the narrative?

I don’t ordinarily put myself in stories, but I thought it was a way to bring the reader along and show them how these things may look to an average person. I became much more part of the story in a way I never expected, in that the more research I did the more I found myself becoming consumed by it. The more honest way to tell the story, then, was to go on an expedition and show my obsession as well.

Is the age of the dashing, intrepid explorer dead?

Fawcett really was the last of the great explorers of unknown territory and blank spots on the map. He would march into areas of the world where a foreigner had not been and, literally, make contact with new civilizations and tribes. There still exists in people a need to discover, but I don’t think it will ever manifest itself in the way it did with Fawcett.

How hard is it to take notes in the Amazon?

It’s okay. I tended to trek so slowly that it wasn’t a big deal.