Growing up, Nnedi Okorafor never envisioned a career as a writer. She had her eye on tennis. Nationally ranked at Homewood-Flossmoor High School, the daughter of Nigerian track stars dreamed of going pro. And after a year playing at the University of Illinois, that seemed a real possibility. Then one day, at 20, she woke up paralyzed from the waist down. Something—doctors never learned exactly what—had gone wrong during a routine scoliosis surgery.

Her tennis career was over, but a silver lining emerged. “I sat in that stinking hospital room documenting my fears and fantasies,” she later recalled in a blog post. Okorafor, now 43, eventually regained her mobility, but those fantasies fueled countless short stories and a pair of breakout novels. The first, 2010’s Who Fears Death, about a postapocalyptic Sudan, was recently optioned by George R.R. Martin for an HBO series. The second, Akata Witch—dubbed “the Nigerian Harry Potter”—led to a sequel, Akata Warrior, coming out this fall.