I am seven years old, my exiled South African family living in independent Zambia, when my teacher asks everyone in class to share a song or a nursery rhyme or a proverb. One kid sings a song in the Bemba language. Another child stands up and performs a dance that is popular at the time. He rolls his little hips lewdly, and we all giggle. When it is my turn, I stand in front of everyone and command their silence with the seriousness of my facial expression. I am stock-still, cradling an imaginary rifle. I crouch and sway from side to side, hissing through my teeth to intimidate my audience. I...