Robert Caro says that interviews about Lyndon Johnson taught him about life in Johnson's era through interviewees' accounts of their grandfathers and their grandfathers' stories.

“Uh, and if even with the, all these other difficulties and all, well, that's sort of in my books because pe- in my notes, because when I was talking to people, they would talk about their grandfathers or what their grandfathers told them, you know?”

“And when I'm talking to them about Johnson, I'm learning all about what life was like in that era.”