David McCullough (1933–2022) was a Pulitzer Prize–winning historian and bestselling author. “Knowing Who We Are” is an excerpt from a speech the historian delivered at Hillsdale College in Hillsdale, Michigan, in 2005. A posthumous collection of his essays, History Matters, that affirm the importance of remembering the lessons of history, was released in September 2025. (Photo by William B. McCullough)