“Marriages are complex and mysterious stories,” the critic and poet Robert Pinsky once wrote. I found this to be the case when I was working on Everybody Thought We Were Crazy, my book about Dennis Hopper and Brooke Hayward, the highly collaborative—and highly combustible—couple at the center of the cultural explosion that was 1960s Los Angeles.

Adding to the complexity and mystery, Hopper and Hayward reside on opposite sides of the divide between history and memory, which can feel both razor-thin and, at times, like an unspannable gulf.