If there were another writer of non-fiction as deeply researched I'd compare McPhee to, it would be Robert Caro. I already knew from Caro's memoir Working that Caro did not use a tape recorder in his interviews with subjects, and from this article about McPhee's method, I learned that McPhee does not either. I'm a bit surprised: I'd have thought for such deep research one would want a recording to refer back to, but both seem to feel that the drawbacks of influencing their subjects outweigh their benefit.