“Immortality: Design Works” stands as one of the most extensive video game art books ever created.

At nearly 600 pages, including the game’s complete screenplay — and more than a dozen bonus trinkets in the Deluxe Edition — Lost in Cult’s upcoming Immortality: Design Works isn’t the sort of book you fit neatly into your collection; it’s the sort of book you build a collection around.

The fifth entry in the U.K. publisher’s Design Works series, the Immortality book dives deep into one of Polygon’s favorite games of 2022, the FMV game that answers the question, “What happened to Marissa Marcel?” Mixing artwork with archival photos, interviews, and analysis, Immortality: Design Works will be shipping soon, so we reached out to get a bit more detail on what to expect.

As part of an effort to spotlight game-related books and documentaries, Polygon is running an email interview series with the people behind them. Check out the full list to read up on an Untitled Goose Game book, a Housemarque documentary, and others. Below, Immortality: Design Works book author Chris Schilling discusses the game, thermo-reactive ink, and Lost in Cult’s highest page count to date.

Polygon: The book looks like it includes a bit of everything. What percentage is the game’s script and what percentage is writing about the game, artwork, etc.?

Chris Schilling: It’s hard to break down into percentages; suffice it to say that the complete Immortality screenplay alone runs to more than 400 pages. The rest comprises a detailed oral history, interspersed with features covering individual aspects of production — from how Half-Mermaid and crew achieved a period-perfect look for three fictional films to the game’s haunting sound design. In total, it’s close to 600 pages, making it Lost In Cult’s biggest individual book to date.

The store listing mentions “thermo-reactive ink that responds to the heat of your hands.” Can you explain how that works and what’s hidden in there?

That would be telling! We’d like readers to discover it for themselves, but the description basically says it all — if you place your hands on certain pages, you’ll reveal what’s hidden beneath the surface. It works if you hold a flame nearby, too, though we wouldn’t advise that!

What’s an obscure detail most people wouldn’t know that you learned about the game while working on the book?

Because of the game’s intricate nature, and how the scenes are interconnected, all the actors had to stick very closely to the script. But there was one moment where an accident forced a particular actor to ad-lib a line, which was so good it was kept in. It’s a really funny anecdote, so readers should look out for that one. Also, one of the production team [members] made an unexpected cameo in the game that no one knows about; again, I’ll preserve the surprise for the book. The last thing I’ll add is that you’ll learn at least as much about the filmmaking process as the game part — just about everyone I spoke to offered illuminating insights into their roles, but chatting with the game’s BAFTA-nominated costume designer Kerry Hennessy was a particular treat: that has to be one of the most enjoyable interviews I’ve ever done.

At a glance, it looks like the Deluxe Edition has about 15 items in the box. Anything you wanted to include that you weren’t able to?

At Lost In Cult we’re always keen to push the boat out and give our readers as much bang for their buck as possible. As a writer, I invariably feel like I could have done more — but extending the page count further could have made an already massive book quite unwieldy! I think the Deluxe Edition makes for a pretty comprehensive package — especially the in-fiction extras which provide some telling extra details. In particular, Manon Gage’s in-character script annotations as Marissa Marcel will be catnip for Immortality fans; discussing those with her was one of my personal highlights of the project.