Just as interesting as the story within the books is that of its author. No one knows who John Twelve Hawks really is, and even his editor has never seen him face to face. He lives off the grid and lives by the message he preaches in his books.
The Fourth Realm provides examples of:
- Action Girl: Maya.
- Another Dimension: The Realms.
- The Ark of the Covenant: The Ark turns up at one point.
- Author Filibuster: There are many, many discourses on invasion of privacy and loss of freedom, but Gabriel's speech near the very end of the story stands out.
- Author Tract: This story exists to alert readers to invasion of their privacy.
- Beethoven Was an Alien Spy: Various philosophers and religious figures are identified as Travelers, including Plato, Jesus and Buddha.
- Confusion Fu: To fight the Brethren, Harlequins "cultivate randomness". They are deliberately unpredictable in battle and go so far as to use random number generators to make decisions in order to confound predictive tracking algorithms.
- Heroic Sacrifice: Vicky, Gabriel (sort of — he's still alive, but it's unknown if he will ever be able to return).
- Meaningful Rename: When someone becomes a Harlequin, they shed their old identity and take on a new name. Near the end of the trilogy, Hollis renames himself Priest.
- Public Secret Message: This is how the Harlequins communicate with each other and with Travelers. They leave graffiti or other notes in public places that have easily detectable second meanings decodable only by other Harlequins or Travelers.
- Shout-Out: When visiting the Third Realm of the animals, Gabriel reflects that he does not meet an allegorical lion.
- Skyscraper City: The eponymous city from The Golden City is actually just three gigantic, terraced towers.
- Superpowerful Genetics: Travelers pass down their abilities genetically.