Andrew Shaffer, Writer for Ghosts from Our Past: Both Literally and Figuratively: The Study of the Paranormal from Three Rivers Press, has conducted a interview about the book, answering many questions given by the Wiki contributors. (Interview Conducted by Matthew Jordan aka: Devilmanozzy)

Basic Questions

1. How did you get the gig to write the book?

ANDREW SHAFFER: A few years ago, I wrote a tie-in to the Sharknado franchise called How to Survive a Sharknado and Other Unnatural Disasters. My editor at Three Rivers Press asked I had any other ideas for another pop culture book, and I immediately said, “Ghostbusters.” Of course, Ghostbusters was a dormant franchise at the time, so there wasn’t really any interest there.

Flash-forward to 2015, and we got word that Sony had greenlit Paul Feig's Ghostbusters. Not only that, but they were looking for a humor writer to do a tie-in book. After reading the screenplay, I wrote up an outline and a sample introduction, which my editor shared with Sony. I'm not sure how many other writers were up for the job—or where their bodies are buried—but I got word a few weeks later that I got the gig.

2. What knowledge did you have about the Ghostbusters universe before writing the book?

ANDREW SHAFFER: I knew the first two movies front to back; I'd seen the cartoons as a kid, and read the short Ghostbusters training manual (which was basically a sticker book). However, I'd never delved deeply into the role-playing game, or seen Extreme Ghostbusters. I'd never dressed up as a Ghostbuster or taken part in any online forums. The second I got the gig, I read and watched everything Ghostbusters that I could get my hands on—not just for research, but also for fun. The wiki really helped me get my bearings, too.

3. Please talk a little about your method for writing this book. As you wrote this book, did you script it chronologically or was out of order - you did Part 2 then Part 1? Did you solely work on this book or did you work on multiple projects at once?

ANDREW SHAFFER: I've tried working on multiple projects at once, but at some point one of them always takes over my life—it's the only way I know how to write, for better or worse. Ghosts from Our Past took over my life for about six full months, beginning last July. The first month or two were spent doing research on the paranormal and science, and trying to figure out a way to connect them in the book that wasn’t too ludicrous. From there, I wrote the book pretty much front to back, although the order of some chapters was switched around during revisions.

4. Which draft of the movie did you get (i.e. 1st draft? 2nd) and was it dated (i.e. December 2014)?

ANDREW SHAFFER: Sony provided me with multiple drafts of the screenplay, from July 2015 through the end of principle filming. I don't recall if they were dated—since they were accessed through a secure system, I don't have copies of them available any longer. Even after seeing multiple drafts of the script, a lot of the dialogue in the final film was still a surprise to me, because it was either improvised or written on set.

Foreword and Introduction

5. In the movie, Martin Heiss was ejected from the Ghostbusters' window by Mayhem and it was played off vaguely if he survived or not. Looking at the revised Ghosts from Our Past (GFOP)'s new foreword by Heiss, it appeared he survived after months of recovery but in the third paragraph on page 17 - it is stated by Abby and Erin that they got an actual ghost to write their new forward. Was this a mistake or intended as a joke that Heiss isn't aware that he died and manifested as a ghost?

ANDREW SHAFFER: During filming, there was a chalk outline of Martin Heiss on the street, indicating that he'd died from the fall. Armed with this information, I wrote a foreword from his perspective—as a Class IV ghost.

However, during post-production of the film, Dr. Heiss's fate was altered to be vague (leaving the possibility open that his character survived, for potential sequels, I assume). So I changed the foreword to reflect that he was alive, but unfortunately missed the joke about him being a ghost on page 17. That will be corrected in future printings of the book.

But, wait! Paul Feig has mentioned in interviews that he's uncertain if Dr. Heiss is alive or dead, so there's still a possibility the foreword is written from the perspective of a ghost that doesn’t know he's a ghost. I guess you could say that Martin Heiss is a little like Schrödinger's cat, in that he’s both alive and dead. Schrödinger’s ghost, perhaps?

Part 1 (Chapters 1-3)

6. Part One of the book vastly expands on the back story of Abby and Erin which was piece meal in the actual movie. In past interviews, you likened it to taking 1 page in the script and writing 100 pages in GFOP. Did you completely write the section from scratch? Did Paul Feig and Katie Dippold provide you a bunch of notes initially about the characters before you wrote or did it get tweaked as you got feedback from them and Ghost Corps?

ANDREW SHAFFER: I wrote a sample outline and introduction to the book, which Paul and Katie both read and provided notes on. They both had ideas on how Erin and Abby would approach the paranormal in the book (from a scientific viewpoint). No character bible, though. Using what was in the script, I wrote the backstory chapters and sent off a rough draft to Sony. Paul read and critiqued the chapters, saying "Erin wouldn't do this," or "Abby would do this," etc.—quite detailed notes. Together, I think we finally got to the heart of the characters.

As an aside, Erin and Abby have slightly different backstories in the Tor novelization. I don't believe that Paul or Katie had any input on that, as novelizations are treated more like adaptations, whereas we were lucky to get more of a hands-on treatment with the tie-in book. Nancy Holder's novelization is fantastic, though—definitely read it!

7. Did any particular chapter - Abby, Erin, high school, college - get revised the most or suffered the most editorial cuts? Was there any material you wish remained aside from Abby's lengthy stay in the woods?

ANDREW SHAFFER: Abby's stay in the woods was a little longer and much harsher, originally—maybe a tad too harsh. There's nothing cut out anywhere that I would add back in, either in the backstory chapters or other sections. My brilliant editor (Matt Inman at Three Rivers Press) really helped trim the fat.

8. Noticeably Erin and Abby had a lot of inspiration from the recently showing X-Files series on TV in 1993. Was this to better time stamp when they had they event with Professor Alderman, or are there any possible parallels to draw?

ANDREW SHAFFER: It was just a coincidence that the timeframe worked out like it did. I've heard many scientists Erin and Abby's age or younger state how big of an influence The X-Files was—particularly Scully, the skeptic. For Erin and Abby, however, I thought they would gravitate a little more toward Mulder. He was mocked for his beliefs, like they were.

Part 2 (Chapters 4-8)

9. Chapter 4 is Ghosts Throughout History. That and chapter 5, are probably the most dense source of information section of the book. Was it always planned from the start to use Erin and Abby's voice to offset a potentially didactic read?

ANDREW SHAFFER: We knew from the start that there would be a lot of technical and historical information in the book, which had the potential to be very dry. There were already a lot of really dry books like that on the paranormal shelves, however. When you slap the Ghostbusters logo on the cover, people have certain expectations—mainly, that it’s going to be humorous.

My rationale for their voices being so humorous: Put yourself in the shoes of two twenty-two year olds. They're going to make some goofy jokes. Especially at the expense of the field that they're trying to revolutionize. Even when they're trying to be dead serious, it ends up being a little goofy, just because they're overreaching.

10. How did you decide on what eras and cultures to write about? Were they chosen for you, were they personal interest, or was it a lengthy approval process?

ANDREW SHAFFER: After reading dozens of paranormal history books, I had an idea in my head about what eras would be the most entertaining to cover. Spiritualism was probably the most fun, simply because it's so recent and, frankly, quite bizarre. People will probably say that about the present day in a hundred years!

11. Was it a deliberate choice to end Chapter 5, Paranormal Investigators, on the Rhine trials at Duke University or was it editorial? Was Feig and Dippold's stance that legitimate paranormal research topped off at that point and stagnated for the next three decades?

ANDREW SHAFFER: Once you get past the Rhine trials, you start getting into paranormal researchers who are still living, which adds another layer of complexity to the project. Since this was primarily intended to be a humor book, I didn't want to spend time worrying if some joke was going to cause legal trouble or something. I filled in some of the gaps with researchers I'd invented, such as Vernon Heiss and Maureen Kemp.

12. In Chapter 6, on page 87, you delve into the Spectral Field Theory. At a glance, it looks like some basic Pre-Calculus and some Differential Calculus with some paranormal terms blended in. Was it your own creation or was it provided to you in one of the script drafts or one of Feig-Dippold's notes?

ANDREW SHAFFER: The wonderful team at Three Rivers Press created the equation for Spectral Field Theory from my notes. We wanted to have a physicist make it more believable, but we didn't have the time, unfortunately. I know what Erin and Abby would say, however: That’s not the real equation anyway. They used basic calculus to throw potential Rowan copycats of their trail.

13. Were any of the science consultants from the movie - James Maxwell, Janet Conrad, or Lindley Winslow - or even Dan Aykroyd available to you for work on the equations, theories, and terms?

ANDREW SHAFFER: James Maxwell read a couple of sections for us, and offered corrections. Dan Aykroyd read an early draft of the book and gave it the thumbs-up. He knows his stuff, so I breathed a sigh of relief after that.

14. Was there any debate about holding onto Tobin or was it always going to be a new character - Kemp - who created the modern classification system from the start?

ANDREW SHAFFER: There was never any debate about it—Paul Feig didn't want to reuse any of the faux books from the original universe, so I had to create an entirely new set of reference guides along the lines of Tobin's. There were one or two mentions of fictional reference books or authors in the script that didn't end up in the final movie, but the ones in the book (Archibald Dutton, Vernon Heiss, and Maureen Kemp) were ones I created just for Ghosts from Our Past. I also designed faux covers for several of the books, which you can find at

15. In coming up with Kemp's spectral classification system, did you ask Feig-Dippold, Ghost Corps, or Aykroyd about any official system or did you look at other sources like the West End Games RPG and your submission was was approved?

ANDREW SHAFFER: Everyone wanted to keep the classification system fairly standard across the various universes, so there wasn't much debate there—not sure if this was Paul's direction or Ghost Corps. I primarily looked at the West End Games RPG, because that's what aligned the best with the original films. (The Real and Extreme systems were quite different.) The Kemp system in Ghosts from Our Past lines up with what's used in Insight Editions' new Tobin's Spirit Guide pretty well, I think.

When you compare the Kemp system to the new movie, there are one or two instances that might be off a bit—the demon Mayhem is labelled a Class III, and the unidentified entity in the subway is referred to as a Class IV. There may have been lines that didn't end up in the final cut that explain those a bit more. I left some wiggle room in the book, though: The Kemp system is twenty years out of date by the time of the events in the movie, so they may be using a different system at that point.

16. The case studies. Again, were these all your choice from a big list that got whittled down? How did you settle on picking from real myth, to made up, to historical figures, to Belushi, to existing Ghostbusters characters? Was Āpshai a favorite of yours from The Real Ghostbusters?

ANDREW SHAFFER: I don't remember how long the original list of ghosts was, but it wasn't much longer than what's in the book. We cut it down to three per class. The illustrations were done by Steven Salerno, working off references I provided.

Since the only spectral entities that appear to cross over between the universes in the film are Slimer and Zuul, I wasn't able to pull from the existing Ghostbusters mythos for this section. However, I did add a few—Cthulhu and Āpshai—that appeared on The Real Ghostbusters. And Belushi's ghost was added as a nod to IDW's comic series, which uses him from time to time.

Cthulhu and Āpshai weren't my favorites, but they seemed like entities that would exist in both universes regardless of whether the universes were bleeding into one another, for lack of a better term. My favorite cartoon villain, for instance, was Samhain, but there wasn't any sort of historical or pop culture precedent to add him into the new universe.

Part 3 (Chapters 9-12)

17. What inspired the "Natural Enemy of the Ghost Hunter" and its illustration?

ANDREW SHAFFER: Casting raccoons as the "Natural Enemies of Ghost Hunters" was a nod to my favorite TV show, Parks and Recreation, where raccoons run amok. It was my subtle way of paying homage to Ghostbusters co-screenwriter Katie Dippold, who wrote for Parks and Recreation.

18. Where did Holtzmann and Patty's sections come from - your own writing or material provided?

ANDREW SHAFFER: Holtzmann's section was mostly cribbed from MIT physicist James Maxwell's notes. Patty's section was mostly my own writing, with a few lines directly lifted from the screenplay. After seeing the final film, I think I got Patty's voice down. Kate McKinnon's Holtzmann, however, is just such a singularly weird character, that there was never any chance I was going to be able to nail down her voice in just a couple of pages.

19. Lacking from Holtzmann's section are the later devices like the Proton Glove or even the working Containment Unit. Likewise, Patty's lacks Stonebrook Theater and Seward Station. At any point, were these sections going to be longer and more comprehensive or was it a matter of editing decisions?

ANDREW SHAFFER: I purposefully left them out of the book. One reason was to avoid spoilers. I knew the book would be out a few weeks before the film, so didn't want to give everything away. Of course, the novelizations ended up being released early, too, so anybody who wanted to know the story beat for beat would have been able to.

The other reason I left them out was because I wanted to leave room for a sequel—I imagined they would cover the events and gear in the film in greater detail in A Glimpse into the Unknown (which is "previewed" at the end of Ghosts from Our Past). While there aren't any plans to publish that book at this time, I wanted to leave the door open.

20. Page 146 seems to note an image (10.2) which is for the Mercado. Is this missing because of deadlines, or did not permit the image to be in the book?

ANDREW SHAFFER: Due to a production error, the image was left out of the book. Future printings will have the reference to the image removed.

21. Was Part 3 a treatise, mixed with personal commentary, on all those ghost hunting books and reality shows (not unlike what that Ghost Jumpers show in the movie was about)?

ANDREW SHAFFER: Yes. I watched a couple episodes of some popular ghost hunting TV shows, and was unimpressed. Who does serious scientific work in the dark? Turn on the lights! The same goes for many of the "real" ghost hunting books I read as research—mostly a bunch of pseudoscientific bull. I could see Erin and Abby rolling their eyes at a lot of the stuff I encountered. My own criticism—if it wasn't filtered through Erin and Abby—would be much harsher, though. I'm a skeptic when it comes to the paranormal.

Timeline Specific

22. General questions about the canon timeline. Was it in 1994 for the first version of GFOP was written and released? When did the events in the film happen? And canon based, when did the GFOP (Newly Revised and Somewhat Updated! version) get updated and then released?

ANDREW SHAFFER: The original edition of Ghosts from Our Past was written and published in summer 1996, after Abby and Erin had both finished their undergraduate work at the University of Michigan. If you look through the bibliography, there aren't any books published after 1996.

I assumed the events in the film happened in either 2015 (simultaneous to filming) or 2016. Some fans have zoomed in on the YouTube video shown in one of the vignettes, which shows that the Aldridge Mansion Museum scene takes place in October 2014... but I'm not sure there’s any significance there. Again, that's just my assumption.

I would also assume that the revised edition of Ghosts from Our Past was released on June 28, 2016 (same as in real life).

23. In a followup, a issue was raised about page 15. Doesn't this seem to suggest that they had already graduated with a degree when they wrote the book?

ANDREW SHAFFER: In May 1996, they graduated with their undergrad degrees from the University of Michigan. Erin was accepted into grad school at Princeton for that fall. Abby was staying behind at Michigan to do her graduate work.

They spent the summer together writing the book, because they knew they were going their separate ways that fall.

Here's their "original" bios from the first edition of the book, published in summer 1996:


Erin Gilbert completed her undergraduate work in Physics and Quantum Mechanics at the University of Michigan. As an undergraduate, she coauthored the seminal paper "Condensed Matter in Transport of Fractional Quantum Hall States." She plans on beginning her graduate studies at Princeton, under Professor Hans Anschutz. She will complete her Doctoral work at CERN and is currently studying Swiss.


Abigail L. Yates is a two-time winner of the Institute for Advanced Theoretical Research Prize for Students, and a recipient of the Westinghouse Dream Beyond Your Ability Award. She holds dual undergraduate degrees in Astronomy and Physics from the University of Michigan, where she will return this fall as captain of the University of Michigan Curling Team. And also for graduate work. Her stated goal is to "blow every mind worth blowing in modern physics."

24. Seems that there is a conflict in writing according to the timeline research over what Martin said, which is the age 22 of Erin. The issue is Erin's age is well established to be 8 years old in 1985. 14 years later would be 1999. Was the Greta DeMille incident in 1981 or still in 1985 but Erin was actually 11?

ANDREW SHAFFER: Ah, I see. The references to October 1985 were an error on my part -- they should have read October 1982. Never ask a writer to do simple math!

The timeline for the book should look like this:

  • Erin and Abby - DOB 1974 (approximate -- we don't have exact DOBs)
  • Erin and Abby - Greta incident in 1982, not 1985
  • Erin and Abby - age 19 (approximately) - X-Files premiered 1993 - sophomore year
  • Erin and Abby - age 22 - graduate 1996 and write GFOP over the summer
  • Erin and Abby - age 22 (approximately) - leave for graduate school

At least that's how it fits together in my mind.

I'll have to ask my publisher to fix it in the next edition of the book. Thanks for catching!

25. Would you consider writing for the old Ghostbusters universe if the opportunity presented itself to you?

ANDREW SHAFFER: Absolutely! My original proposal for a Ghostbusters book was an updated Tobin's Spirit Guide, which I later found out was already in production. I’d love to return to the Ghostbusters universe (old or new).

26. What other books and projects do you have coming out?

ANDREW SHAFFER: I recently published The Day of the Donald, a satirical thriller about a Donald Trump presidency (though it gets less satirical by the day…). I have a couple of other projects in the pipeline, but I’m superstitious about talking about things until they’re finished. It's my one superstition!

Thanks for interviewing me! The wiki is a fantastic resource for fans. Keep up the good work!

Interview Conducted by Matthew Jordan (aka: Devilmanozzy).

Community content is available under CC-BY-SA unless otherwise noted.