I Lived in a Van to Write the Book Behind ‘Nomadland.’ The Fear Is Real.

Spending the first night in my 1995 GMC camper van, I lay awake for hours in my sleeping bag, watching the window shades glow — white, then red, over and over — as cars sped past in the dark. Is that one slowing down? I wondered. Can they see I’m in here? Will they call the cops?

Van dwellers had told me about “the knock” — usually three sharp raps at the door, often by the police. The risk of getting jolted awake and kicked off my patch of asphalt...