In the afterword of the most recent Resident Alien collection by Peter Hogan and Steve Parkhouse, Peter shared the origin of the name of the third volume's name…
One night in the rainy October of 1990, I was walking down London's Oxford Street with Neil Gaiman, and it being October we were discussing Halloween—and the fact that it used to be called Samhain. "I know it's pronounced differently, but I've always thought that Sam Hain would make a great name for a pulp detective." said Neil.
Fast-forward twenty years or so…I had a vague idea for a story about a fictional pulp detective, and I remembered Neil's idea. Since he'd never used the name himself, I asked Neil if he'd mind me stealing it for use in Resident Alien. He didn't, so I went right ahead and planted some Sam Hain novels in Harry's bedroom during the course of The Suicide Blonde. and then brought Sam center stage (kind of) for this story.
All Neil asked in lieu of a fee was that I should bury him in the story in a shallow grave—which is why you'll find a head-stone reading "Mr Punch" in Rebecca's pet cemetery. I should probably also point out that the real Neil is a lot nicer than the Neal in this story, but you know that already.
Peter Hogan – Walking In Space 2015