Journalist Annie Jacobsen gained a certain degree of fame last year as the woman who wrote about the strange and frightening behavior of a group of Syrian “musicians” aboard a Northwest Airlines flight. She has now written a riveting book, Terror in the Skies: Why 9-11 Could Happen Again about what happened that day and in the months that followed. Jacobsen put her investigative skills to work, and discovered that the harrowing events that took place on her flight were far from an isolated occurrence. She ends her book with a warning: If our security system does not improve, another...