Writing—or editing—a trilogy is not for the faint of heart. The process takes years, multiple drafts, and frequent reversals of course to accommodate new ideas. Notes for future subplots fill Mole-skine after Moleskine, untied strings dangle from chapter after chapter. It’s a high-wire act that requires enormous attention to detail and a knack for crafting plots with enough room to permit improvisation. It’s a bit like trying to build a skyscraper while the architect keeps fiddling with the blueprints. But if you do it right you have a built-in audience for your next book, and the one after that.

This fall, after a decade in which the multi-book series only seemed to outnumber stand-alone novels, several authors are bringing their high-profile trilogies to a close. Many readers literally can’t wait. Veronica Roth’s Allegiant, the conclusion of her Divergent series, doesn’t arrive until October but already has a bestseller sales ranking on Amazon.com.

The editors of these books completely understand the concept of fevered anticipation.

“To me, reading the subsequent books in a series you love is like being reunited with your best friends from camp,” says Jen Besser, who edited Marie Lu’s Legend trilogy for Putnam. “You don’t see them for a whole year but when you return the next summer, you are just so happy to see them again that, in an instant, it’s like you were never apart at all.”

Like many readers, Besser geared up for Lu’s second and third books by rereading book one, but some editors deliberately skip the refresher. Kathy Dawson, who edited all three of Gennifer Choldenko’s Al Capone books for Dial, starts cold with each new manuscript. “I want to see how it reads if you haven’t read the first one, or the last one, or if you did read them but it was a year or two ago,” she says. “Ideally, we don’t want to strand a reader who hasn’t read the previous books. And we don’t want to bore anybody.”

Ah—the info dump. Editors agree it’s one of the trickiest parts of series writing. “I prefer a minimal amount of catch-up,” says Kate Farrell, who brought Kirsten Gier’s Ruby Red trilogy to the U.S. market for Henry Holt. “It’s dull to read when you’re eager for the new stuff and don’t want those old details clogging up the works.”

Another important task is making sure the details are consistent in a series that might easily span 1,000 or more manuscript pages. Any office supply item you can think of has been employed to manage a complex plot—highlighters, colored index cards, binders, corkboards (for pinning up photos, maps, and color-coded index cards). It’s all about finding a process that works.

Besser says the Putnam staff created a series “bible” for the Legend books, against which every detail was checked. Dawson’s magic wand is Dial copy editor Regina Castillo. “She’s miraculous. She checks every eye color, hair color, all the peripheral characters’ names, everything,” Dawson says. “I cannot tell you how grateful I am to have someone who makes sure those things are correct before we have a finished book so I can focus on the emotional stuff.”

Emotion: that’s what every editor is looking for in a finale. But be careful what you wish for, warns Martha Mihalick, who edited Rae Carson’s Girl of Fire and Thorns series for Greenwillow.

“It’s not a sad ending at all but when I finished it, I burst into tears, which is not like me at all,” Mihalick says. “I loved the whole thing so much—I didn’t want it to end. I cried because I was just so sorry it was over.”

To get the author perspective, we spoke with nine writers whose trilogies draw to a close this fall (a 10th, Veronica Roth, was unavailable). They shared what it takes to keep dozens of characters and thousands of pages straight—and how it feels when it’s all over.

Gennifer Choldenko, Al Capone Does My Homework
Rae Carson, The Bitter Kingdom/Girl of Fire and Thorns
Marie Lu, Champion/Legend
Kerstin Gier, Emerald Green/Ruby Red
Veronica Rossi, Into the Still Blue/Under the Never Sky
Gabrielle Zevin, In the Age of Love and Chocolate/Birthright
Ilsa J. Bick, Monsters/Ashes
Julie Cross, Timestorm/Tempest
Neal Shusterman, UnSouled/Unwind