In 1965 the eminent American science-fiction writer John W Campbell wrote an essay titled The Barbarians Within. In it, he recommended that “the barbarian” – and it was clear he meant African Americans – be injected with cocaine and heroin in order to be kept under control. It was a plan that, he said, “has the advantage … of killing him both psychologically and physiologically, without arousing any protest on his part”. He also claimed that slavery was “a useful educational system”, supported segregation, and argued that “the Negro race” had failed to “produce super-high geniuses”. Black sci-fi writers were unable to “write in open competition” with whites.

In 1960, Macmillan rejected her manuscript for The Mystery That Never Was on the grounds of xenophobia