Six months ago almost no one had heard of Adaeze Okafor. Her debut shipped a modest first printing to a handful of shops. Today it is on its ninth.

The story of how The Cartographer’s Error became a phenomenon is partly luck and mostly booksellers — the independent shops that pressed it into readers’ hands one copy at a time.

The long tail of a whisper

There was no marketing blitz. There was a novel good enough to talk about, and a network of readers who did.

"It spread the way books used to spread," one bookseller said. "By people saying: you have to read this."