Creator Breakdown: Morrison's father died during the writing of this book, which probably led to the scenes where Clark Kent had to deal with Jonathan Kent's death as well as talk with Jor-El in the afterlife.
Jossed: A very popular theory is that Leo Quintum is, in fact, Lex Luthor, having undergone a HeelFace Turn and traveled back in time. Morrison himself, however, jossed that theory.
Shrug of God: When asked about the book's continuity with All Star Batman, Morrison is vague and indifferent about it. According to him, the continuity is possible since Batman takes place during the start of the Dark Knight's career while Superman was at the near-end of the Man of Steel's life.