Van Helsing said that a vampire couldn’t come in unless you invited him. If it was true of vampires, it stood to reason (at least to thirteen-year-old me it did) that it was true of other supernatural beings. Like the one inside of Therriault, keeping him from disappearing after a few days like all the other dead people. I checked Wikipedia to see if Mr. Stoker just made that up, but he didn’t. It was in lots of the vampire legends. Now (later!) I can see it makes symbolic sense. If we have free will, then you have to invite evil in.
