In 1981, when my identical twin sister, Deane, a psychologist, and I were 32 years old, she was fatally wounded by one of her patients in Lowell, Massachusetts, just outside Boston. Another doctor died at the scene, and two other people were wounded but survived. Deane had that morning given her PHD thesis to a typist. She was going to travel to Knoxville that day to spend ten days with me. I woke up and put a bottle of champagne in the refrigerator, wrapped her present, signed a card addressed to Dr. Deane…