In the beginning was B, who looked like an angel. He asked to carry my books up the hill. It was the first day of sixth grade at my new school, in a new city, San Francisco. It began to rain. A tough and intimidating eighth grader approached. (She and her friends looked like adults to me, and, as I soon discovered, they had adult problems, like pregnancy and drug addiction.) She took my umbrella and said something unrepeatable about B’s race. He was black, and she was stridently white. Many things were new to me that day. B and I never reconnected. All the girls in my grade liked D, who was a natural leader with a demonic personality. (I’ve given these people random initials.) D made fun of me for being smart and having freckles, which was considered a form of ugliness. He once stole the lever at the top of the stairs in my apartment building, which you pulled to unlatch the front door without making the long descent. My parents, science postdocs who were often at the lab and were unversed in the delinquent world of the Sunset District, were upset about the lever, since we rented. It was brass and heavy, and D, who was white, said he planned to use it to bash people’s heads in. For a few days that year they closed my school, where white kids and . . .