When the BU School of Law community lost Professor Mark Pettit, Jr. last summer, we lost a great teacher, perhaps the best law teacher in the United States. His classes sang even when he was not singing. I have an overwhelming feeling of gratitude at having been Mark’s friend and colleague for the past thirty-four years. When my friends at the Mandel Legal Aid Clinic at the University of Chicago Law School learned I would be teaching at BU Law, they urged me to seek Mark out. Mark taught there as a clinical instructor before he came to BU, and his former colleagues told me that Mark was a great person, a fantastic colleague, a great law teacher. Mark proved worthy of their praise on many different levels