Aine, this is one of my very favorite Twilite Zone episodes. The man who discovers the name of the book "To Serve Man" was a decoder and was able to decode the title, but not the text. He had a young woman assistant that worked with him. They worked on for some time when it became the man's turn to take a much desired trip to their friends, the Aliens, planet. As he was boarding the ship, up runs the girl screaming, "John, John, (It may not have been John), don't go!! The book, the book!! It's a cook book!! Gives me chills everytime I think of it.
I like "Angel". Lurking suggests to me, to me now, something subversive..oooooooo. Old school too, I guess.