The spark behind the latest bouts of race violence in the US, leading to the shooting down of five police officers in Dallas, was not a singular one: it was an accumulation of collective rage over a largely white police force’s treatment of blacks. It brought back to me the time I had gone to see Martin Luther King, Jr. in his office in Montgomery, Alabama. It was 1957 and I saw signs that said “colored lunch” (I hadn’t realised lunch could be coloured) as I proceeded to my destination. I waited in his secretary’s room until he emerged from a meeting. He was affable and sat for a while kidding his fetching secretary. He told me he could not grant me an interview because he needed to go home to nurse a bad cold.