Dexter spoilers for the TV show and books.
Spoiler:
"The dark passenger is similar to his father - it is a construct of his mind. Nowhere in the book does it manifest itself as discrete from Dexter."
That's not how I read it. We must have had different interpretations, but to me it was pretty clear that Dexter was being possessed by an ancient demon. The book also mentioned the kids had their own "dark passengers," ie demons possessing them.
"Dexter is Delicious is not about vampires. Not in the slightest."
Like I said, I didn't read it. I gave up after book three was so terrible. But I know someone who has read all of the books so far and he said that book was about vampires. Maybe he was wrong.
"Some people know - his immediate family - that's hardly the whole town."
When I said "the whole town" I was not literally talking about every person in the city of Miami. I meant the major characters in the books. A bunch of them know who he is, unlike in the show where no one knew except characters who showed up for one season and either got killed or left town. Now Deb knows, apparently, but I gave up on the show earlier this season too.
But regardless, that doesn't change the fact that the books aren't worth reading, in my opinion. The show is worth watching, up until the latest season with Colin Hanks and Edward James Olmos. The first book is decent and the second one is okay, but I wouldn't read any further than that.