For the Robert A. Heinlein novel
- Mutually Fictional: A core principle of the "World as Myth". See Recursive Canon for more fun with this.
For the Iron Maiden album:
- Based on a Dream: The titular song was inspired by a nightmare Harris experienced following viewing Damien: Omen II.
- Cut Song: The album was running too long to sound good on vinyl so the band had to decide between "Gangland" and "Total Eclipse." Though the other band members (especially Dickinson) expressed preference for Total Eclipse, Harris decided the song was a bit too experimental for Maiden and so Gangland was used instead. Total Eclipse was ultimately released as a B Side to the Run to the Hills single, which came out a few weeks before the album. "Total Eclipse" was also used on the original Japanese LP of the album but removed on subsequent pressings. Nowadays, Harris feels "Total Eclipse" should have been on the album instead of Gangland. The CD remaster of the album includes both songs in the original intended order."We just chose the wrong track as the B-side. I think if Total Eclipse had been on the album instead of Gangland it would have been far better."-Harris
- Enforced Method Acting/Throw It In: Martin Birch asked (then new) singer Bruce Dickinson to do take after take after take for "The Number of the Beast" (the song). Bruce was obviously frustrated and annoyed, and that's when Mr. Birch told him something like 'now it's time to record the scream', which he of course delivered in a very inhuman way, which he was never able to replicate.
- Magnum Opus Dissonance: Fans love this album, but Steve and Bruce prefer the successor, Piece of Mind.
- Manual Misprint:
- The liner notes for the 1998 reissue on "22 Acacia Avenue" weren't able to fit all of the song's lyrics on a single page, and end up being flat-out misleading about certain word placements. The CD jacket also mislabels the track-lengths of every song by a few seconds short, but noticeably lists "22 Acacia Avenue" as 4:49 instead of the actual 6:38, and the title track as 3:50 instead of 4:51.
- It also has a weird umlaut (but not the heavy metal kind) on one line in "Gangland" ("How long 'till they come?", which becomes "How long ëtil they come?").
- What Could Have Been:
- "Gangland" was chosen over "Total Eclipse" for inclusion on the album when it started running out of space, due to the latter being too progressive, according to Steve Harris. He regrets that decision to this day, yet modern pressings include both.
- The band had originally asked Vincent Price to recite the opening quote for "The Number of the Beast", but Price refused to do it for anything less than £25,000, so they went with Barry Clayton.