Professor of English at Harvard, Elaine Scarry has written a book on how people think during emergencies and what can be done to improve our capacity to cope with disaster. "Scarry argues that one of the dangers of an emergency is that it allows a break from our usual norms, with one of the more dramatic examples being emergency rule. The roots of emergency rule are traceable to a concept in ancient Roman law known as 'justitium' which suspended normal business and granted the emperor additional powers during difficult times of invasion or succession."