How does the author use foreshadowing in The Professor and the Madman: A Tale of Murder, Insanity, and the Making of the Oxford English Dictionary?

The Professor and the Madman: A Tale of Murder, Insanity, and the Making of the Oxford English Dictionary is a nonfiction book. Foreshadowing is not applicable. Winchester does, however, starts the book off with a teaser. He is fascinated by his subjects as individuals, and he often delays revealing certain details of their story, only to reveal them later.