Imagine for a moment that Indiana Jones found his way into the Star Wars universe. He’s an archaeologist, but also part anthropologist, sifting through the artifacts and creatures of the galaxy far, far away – identifying their purpose and giving them identities.

That’s actually a real job.

It’s held by Pablo Hidalgo, a creative executive with the Lucasfilm story group who turns his knowledge into comprehensive guides exploring everything from giant starships to teeny-tiny background characters and props. His latest book is Star Wars: Rogue One – The Ultimate Visual Guide.

Hidalgo is one of the people who walks through each film’s creature shop and figures out the names and backstories for many of the aliens and monsters being shaped there. He’s also one of the most prominent Star Wars authorities on Twitter, answering and debunking questions about canon – and deflecting others for the sake of secrecy.

We spoke with him for Behind the Scenes on EW Radio, Sirius XM 105 (Wednesdays, 6 p.m. ET, 3 p.m. PT) about his life as the galactic Dr. Jones. Here’s an edited version of that conversation:

ENTERTAINMENT WEEKLY: Where did you start? How did you get involved in this project, documenting the furthest reaches of the Star Wars story universe?

PABLO HIDALGO: Well, it really kicked off [last year] with The Force Awakens Visual Dictionary. I had already had a relationship with DK, which is the publisher that creates these books, because I had worked on a project a few years back called Star Wars: Year-by-Year which was a history of Star Wars as a franchise, as a brand. And in my own personal writing experience, I’ve done a lot of source material for Star Wars, dating back to the old role-playing game in the ’90s. So I had had this background of writing for and in the universe.

How does the partnership between you and the creature shop work? Because when I talk with Neal Scanlan and those guys, they’ll refer to creatures as “Ackbars” when fans know the crustacean aliens are called “Mon Calamari.” They come up with nicknames, but you give them actual identities.

So there’s the production reality of what the creature represents, and then there’s the story universe reality of what the creature is. So whenever possible, I try to talk to Neal and his crew and find out what was the thinking behind this creature? And using that as foundation, I’ll then come up with a backstory that fits the narrative, that fits with what’s established and known in the universe and hopefully really try to encapsulate and hopefully enhance what it is that the creature department had thought.

Can you give me an example from Rogue One?

Well, here’s an example from Rogue. Jedha, the occupied city, was very much a war zone, and we saw people that were damaged by the combat and the violence that happens in that arena. We saw a lot of cyborgs and people with missing body parts and whatnot, and those barely really make it onto the finished film. They’re really more background pieces and more atmosphere, but they’re really amazing, incredible designs, so a book like [The Ultimate Visual Guide] allows us to show it off in really nice photography and get some of that narrative into the storytelling space. It’s like, “Yeah, this character is missing a head. Why is he missing a head?” Well, it turns out there’s a potential for a whole larger story in that if you follow the threads that are in the book.

Image zoom Lucasfilm

You even have photos of them. So the “Decraniated” are the people who’ve lost their heads in this battle?

So that’s an example of a design element in Rogue that was called in the production nickname, “The Headless Geishas,” and they’re these servers that you see at a café that have the tops of their heads removed and replaced with these droid components. That was all that was really established. That’s it. It’s just a very superficial, very creepy vibe, but [the book] is an opportunity to show that photo and expand that story a bit more.

Tell me about another Jedha civilian, Nesta Term, who is seen only briefly in the film, but actually looks a little like the masked Guavian death squad who chases Han Solo in The Force Awakens. Here you reveal a kind of moth-like death cult.

The really interesting thing about Jedha was the thematic idea behind the world. It’s this crossroads of all these different faiths, and some of the faiths in my expansion of it in the visual guide is some of those faiths are benign. Some of them are benevolent, and some of them not so much. To create this sort of mixture of different cultures inhabiting this space, I chose that particular character and what they represent, what she represents as more of a death cult just because it look so ominous, you know?

These things you create, the names and backgrounds, often end up being fed into other creative works, correct? Novels, games, comics, the Star Wars TV series Rebels… Constable Zuvio didn’t get any screen time in The Force Awakens, but he had a starring role in Landry Q.Walker’s short story collection Star Wars: Aliens.

Correct. One of the advantageous things about where I happen to be in the company in that as part of the story group, we review and we help develop all this ancillary storytelling, so I’m up to speed on that material, and I’m able to put it into the Ultimate Visual Guide either as overt references to upcoming material or just hidden things that will pay off in the months to come.

So there are more revelations embedded in it?

I will say this much: this book was written largely last year but it will continue to inform as you watch the second half of Star Wars: Rebels because all that stuff was in production at the time, so there are hints and elements and things like that that will keep popping up. This book doesn’t really go out of date because we’re so far ahead of things, you’ll start realizing, oh, my goodness, the book was referencing something that was still maybe even over a year ahead of when it actually comes out.

Was Saw Gerrera and his detective work on Geonosis one of those threads? You weave that into your guide before anyone would see that episode of Rebels, which just aired, in which he uncovers the construction location of the Death Star?

Absolutely. That’s — like, we have this whole backstory, this whole chronology of the history of the Death Star that were — is being exposed in different storytelling over time. Obviously, Rogue One is a huge part of it, but Rebels is a part of it, some of the comic books that we tell are part of it, and I think the Saw Gerrera episodes of Rebels is a perfect example where we’re able to tell a story, and then you realize that a Darth Vader comic that came out almost two years ago is in reference into something that’s been in development all this time.

Another example would be Vader’s castle on Mustafar.

People see it in Rogue One and appreciate it for that, but then the more you think about it, you realize the season finale of Rebels, way back in season 1, finishes off over Mustafar, and there was a reason for that, and all these pieces are finally starting to connect.

Your Rogue One Ultimate Visual Guide is about twice the length of The Force Awakens Visual Dictionary. What accounts for that?

This is DK looking to experiment with a new format, essentially. It was a given when The Force Awakens was coming out that we would have the classic visual dictionary-styled book, and we would have the classic cross-sections book. For this [Rogue One] standalone, we decided, well, how can we do something that’s different? And essentially, what we’ve done is combined those books into a new format, and it’s the Ultimate Visual Guide.

Image zoom Lucasfilm

How much are you pulling from real life to make the details of these machines sound believable?

Absolutely. I looked at real-world tanks as foundational stuff so that I could at least get the language right and make it seem like what I’m talking about comes from a grounded place. I really have to credit Kemp Remillard, the artist who does these cross-sections, and he works really closely with the [Industrial Light and Magic VFX] department and the Lucasfilm art department to make sure that what he’s depicting, it can absolutely be truly representative of what was intended by the filmmakers.

What fascinates you about cross-sections of these vehicles?

I’m the kind of kid who loved the blueprints that would come with G.I. Joe toys, that would tell you all the technical details. Growing up, one of my favorite things that I had as a comic book was the official handbook of the Marvel universe where this artist named Eliot R. Brown would attempt to work out how Iron Man’s armor works or how an Avengers Quinjet works. I ate that stuff up.

What can we infer from the fact little Jyn Erso knows who the droid bounty hunter IG-88 is — but thinks he’s cute enough to be a homemade toy named Mr. Iggy?

This was my hands-down favorite spread of the book. Just trying to extrapolate what a child would name these things was a lot of fun. Regarding Mr. Iggy, you know, the IG droid, we established that as a type of droid, so I don’t think she particularly knows IG-88, the one individual character, but she at least may know the droid type. I imagine Galen maybe made that for her, and she asks, “Well, what is it?” And he’s like, “It’s an IG droid,” and she just throws out that name and says, “No, it’s Mr. Iggy.”

Image zoom Lucasfilm

Another surprise in your book. Darth Vader is only 41 in Rogue One! How did I get to be the same age as Darth Vader?

[Laughs] Well, he was only 9 in The Phantom Menace, so that’s what we have to work off of, and, yeah, you come to realize, boy, that was a tough 40. Being on the dark side really does age you rather prematurely, and as we get older, as us Star Wars fans get older, you start realizing that the characters that you identify with are now younger than you! Time passes, doesn’t it?

Do you have a favorite Easter egg hidden in the book?

One of my favorite Easter eggs, I got to say, I’m a They Might be Giants fan. It’s very hard to find a nerd who isn’t, and in coming up with a callout for someone’s outfit, I had to call it “the blue gown of the sullen moon” which was is a reference of their song, an obscure song, a B-side on a single called “The Nightgown of the Sullen Moon,” and that is, like, really, really in the weeds. That is a deep cut.