Grant Morrison and Frank Quitely’s superb All-Star Superman appears in an oversized “Absolute” hardcover edition this week. It’s one of the best Superman stories ever created–a beautiful encapsulation of everything that’s great about the character. As with a lot of Morrison’s work, it’s also filled with tiny details that don’t call attention to themselves but deepen the story for those who notice them.

There’s one series of details and comments that’s particularly clever, and runs through all of All-Star Superman. The revelation it points toward is never explicitly stated in the course of the story, but if you go back and reread the series with it in mind, there’s a lot of evidence backing it up. A few people were batting it around as a possibility when the story was originally serialized; if you’ve read All-Star Superman, you may have figured it out yourself. Or you may want to figure it out, based on the following question: What does Lex Luthor do after the end of the story? (More on Techland: Superman: All the Anniversaries)

To avoid spoilers, click through for the answer.