Stuart Gibbs is the bestselling author of the Charlie Thorne, FunJungle, Moon Base Alpha, and Spy School series. We asked him to supply some reflections on hitting the 10-book milestone for Spy School.

When I first published Spy School, back in May 2012, I hoped the book might do well enough to warrant a sequel. Now, just over 10 years later, the 10th book in that series—Spy School Project X—is about to come out. I am absolutely stunned—and thankful—that the series has done so well.

The question that I (and most other authors I know) get asked the most is, “Where do your ideas come from?” It’s tricky to answer, because ideas don’t come from any one place. A single book is the result of thousands of separate moments of inspiration, some of which might have come to me several decades apart.

The original idea for Spy School came to me when I was in fourth or fifth grade. I had just seen my first James Bond movie and had loved it. Or, more to the point, I loved James Bond. He was so suave and debonair, even in the midst of an action sequence. I wanted to be him—but even then, I was aware that no mere human could possibly do everything that Bond could. I thought the idea of a kid like me even attempting to handle a Bond-style mission—and failing—was extremely funny. Thus, my hero, Ben Ripley, is supposed to be a proxy for all of us: a relatively normal person dropped into a high stakes spy mission and floundering his way through.

That idea from grade school stayed with me, and over the years, I came up with concepts for other characters. I wanted the best student at spy school to be a girl, and eventually realized it would be fun for her to be a legacy, someone for whom espionage is the family business: Erica Hale. I conjured Alexander Hale because it occurred to me that anyone who appeared to be as good a spy as James Bond was probably faking it. Mike Brezinski is an amalgam of friends I had over the years who were much cooler than me.

All those characters were the main reason that I wanted to turn Spy School into a series; after creating them, I didn’t want to say goodbye to them. Plus, I wanted to continue to build on the character dynamics that I had already set up. Spy Camp came about because I realized that I had never had a scene in Spy School where Erica and Alexander were together and thought it’d be fun to have them on a botched mission together with Ben stuck in the middle. As the series has gone on, the plot for each book has, in part, been driven by me wanting to expand my characters’ relationships in some way.

My decision to locate the school in Washington, D.C., was tied closely to fact that I lived there when I was in kindergarten and first grade—and I have returned to the city many times over the years. D.C. may be one of the easiest cities in the world to do research because so many of the city’s landmarks are free to visit. While I was working on Spy School Secret Service, I found myself in a cab passing the Museum of Natural History with half an hour to spare. Inspiration struck! I hopped out, ran into the museum, and was able to map out the action sequence that takes place there.

In fact, travel has also been a major inspiration for the Spy School series. From the very beginning, part of the allure of the James Bond series was its many locations. (Fun fact: when Dr. No came out in 1962, only 2% of the American public had ever traveled abroad, so even a relatively close location like the Bahamas was considered exotic.) Bond movies introduced me to places like Venice and Rio de Janeiro and ski resorts—so it’s probably not surprising that many of the ideas for Spy School have come from my own travels. I couldn’t have written Spy School at Sea if I hadn’t spent a week on a cruise ship. My children helped me work out the final action sequence in Spy School British Invasion during a trip to the Eiffel Tower.

My own curiosity about the wider world has also driven many of the Spy School plots. I love reading magazines and nonfiction books, visiting museums, and talking to experts in various subjects, all of which spark inspiration. Often, travel and research work in tandem: the idea for Spy School Revolution came during a brief visit to Mount Vernon during a break between presentations at nearby schools, when a docent mentioned to me that George Washington had been the nation’s first spymaster. I then did a deep dive into Washington’s spy ring, and eventually crafted the plot of that book.

Character, travel, and research are all important sources of inspiration for my novels, but there is one source that is particular to the Spy School series alone: those iconic spy movies. After all these years, I still love James Bond—and spy films in general—but I recognize that many of them are ridiculously flawed. From the very beginning, much of the humor in the Spy School books has been rooted in exposing those flaws. Why would an evil organization build self-destruct buttons into their lairs? And where would they recruit the thousands of people they’d need to ruin their evil operations? How can James Bond always work his brand-new gadgets with ease when no one I know can even work their own TV remote? How can a character in Mission: Impossible easily slip on a mask and look perfectly like someone else when, as any kid who has ever celebrated Halloween knows, every mask that has ever been made never looks anything like you’d hoped it would?

I should probably end by noting that it’s fun to come up with ideas for Spy School books. I really enjoy imagining what could happen to my characters next, brainstorming new plots, and watching spy movies for inspiration. As a result, I have plenty of ideas left for further books, so who knows? Maybe in another 10 years, I’ll be celebrating the 20th book in the series.