I remember the day I walked through Foyles bookshop in Tottenham Court Road and literally stopped in my tracks. I’d spotted Do You Dream of Terra Two? on a shelf in the distance and was trying to discern whether the cover truly featured a Black girl in an astronaut helmet. I ran over. No, I wasn’t hallucinating; she was really there. It sounds ridiculous, I’d read a million books set in space, but I’d never seen a Black girl on the cover of a space adventure before. My eyes zipped down to the author’s name. Temi Oh. My heart gave a leap of excitement. I was 98% sure the author was Nigerian. I put Google straight to work and a few weeks later I was sitting in a West London coffee shop with Temi Oh, gushing over that arresting cover.  “You don’t really get a lot of control over the cover as a writer,” she’d admitted. “I told them I definitely want a Black woman. I was really happy especially as I spent a lot …