The Wright Brothers, on a winter day in 1903 at Kitty Hawk, North Carolina, changed aviation history. But there were many slender threads, as David McCullough explains in his well-written book. In high school, Wilber was smashed in the face with a hockey stick, knocking out most of his upper front teeth, by a man later convicted of mass murder. Talk of a scholarship to Yale University for Wilber ended. His mother was quite ill, and he became her nursemaid, as well as cook, house cleaner, a recluse but a voracious reader. This event shaped his life. I now read biographies of famous people in history and identify the many slender threads that came together to make history happen. Such moments add to the drama, and also to a sense that “divine providence” may have intervened. It’s hard to read biographies, or reflect on the meaning of one’s own life, and view everything as entirely random.