(l-R) Neil Gaiman, Margaret Atwood and Stephen King have revealed their tales of lonely book signings early in their careers. Composite: Getty Images/AFP When Chelsea Banning, a debut author, vented on Twitter about no one showing up at her book signing, she didn’t expect that some of the world’s most famous authors, including Stephen King, Margaret Atwood and Neil Gaiman, would respond with tales of their own nightmare public appearances. “At my first Salem’s Lot signing, I had one customer. A fat kid who said, ‘Hey bud, do you know where there’s some Nazi books?’” King wrote to her. “Terry...