Writing a multi-book series is a bit like trying to get your arms around an elephant: even if and when you succeed, you feel like you have been stretched to the breaking point. This fall, the authors of several bestselling YA series delivered concluding books. We asked each how they started, how they managed, and how they felt when it was over.

Holly Black

The Queen of Nothing (Little, Brown), finale to The Folk of the Air trilogy, in which a reverse changeling finds herself caught in a web of royal faerie intrigue.

The first book in the series—The Cruel Prince—was published in January 2018. You wrote a whole trilogy in under two years?

That sounds rushed but I had a lot of lead time. Queen of Nothing was done, or at least, I had turned in a draft before book two [The Wicked King] was released so I was never on a schedule where I was not ahead. The thing that was really nice was that I was never thinking about people’s reaction to what I was writing. I wasn’t drafting it with people’s comments in mind.

You have written a bunch of multi-book series. Does it get easier?

Yes, I think as a writer some things do get easier or at least, you’re more familiar with the hard parts or you know that the hard parts don’t signal that you’ll never figure it out. It’s easier because you know more tricks.

Do you remember where you got the original idea for the series?

It was actually an older idea I’d had for a while, wanting to write about a reverse changeling—a human baby raised in the faerie world. In this case it was three girls, whose parents are murdered by a guy who then raises them as his own.

How do you juggle plot threads across multiple volumes?

I really want to be a plotter and for the first time, I felt like I improved. I knew a lot more of the story in advance than I ever have before. I tried to plan the breaks so I knew where each book stopped. That is extremely useful.

Were there any surprises in the writing/editing process—unexpected plot turns or character developments?

I definitely had moments where I figured something out and had to make a big change that was not what I had expected. I actually get asked this question all the time and the thing is, I never get to be surprised. I only get to know that something is not working. ‘Surprise!’ is the answer but when I get that idea it’s an ‘aha’ moment and a huge relief. I never get to experience the delight of surprise. It’s always relief from the crashing horror of thinking maybe this is the time I will not figure things out.

Does fan response to the initial book shape subsequent books?

I don’t think I’ve ever been this ahead of schedule, so it’s a unique experience to be able to say it was not a factor in this series. One of the things you want to be able to do is write in a space where it’s just you and what you want for the characters. That said, it’s also nice to get feedback from readers and get a sense of where people were and if there were questions everybody needed to have answered.

Did you know from the beginning how it would end?

I knew what the ending was before I started but there was a big thing in the third book that I did not know and did not understand and I had to change a lot as a result. The question for my main character was, what is she willing to give up to rule everything and as a result be safe? What would she sacrifice for power and how much would that push her away from her own humanity? To get her to the crux of that question I had to, well, novels are devices for putting protagonists into the worst possible moment of their lives, and I did that to Jude.

How hard was it to leave the world of this series?

It’s mostly relief, I think. I’ve been writing in the faerie world for a long time but every time I finish a book I feel like I’m pulling off a magic trick of some kind and each time it feels like one day the rabbit will not come out of the hat. So when I get to the end there’s a profound sense of relief that the rabbit came out of the hat again.

What’s next?

I’m actually working on an adult book right now but I’m still figuring out the mechanics of the world and the magic system, so I’m currently deleting more words than adding. After that I am sure there will be more faerie stuff in the future.

Kendare Blake

Five Dark Fates (HarperTeen), conclusion to the Three Dark Crowns quartet about triplet sisters who must fight each other to the death so that one can become queen.

The first book published in 2016. What was your original inspiration?

I may not be able to say this for any of my other books but I definitely remember where this story began. I was at a book event in Oregon that had both indoor and outdoor components—it was more like a festival with authors and music. There were food trucks outside including a hot dog truck. Everyone around it was pointing to something stuck to the tree behind the truck. It was a ball of bees. People were saying we have to cancel the event. Children will die. It was a buzzing, thrumming ball made out of bees. Luckily, there was a beekeeper at the festival and she explained that when the queen [bee] decides to move the hive, the other bees form a ball around her. Their only concern is protecting the queen who is in the center of that ball. And right before they move, the queen lays four or five queen bee eggs and when they hatch they fight to the death until there is only one survivor and she takes over the hive. I was like, whaaaaaat? I started working on Three Dark Crowns immediately.

Do you outline? How do you keep plot threads from dropping across multiple volumes?

Well, the original plan for this book was a duet so I wasn’t as good about having a plan as you might think. Instead, I thought of the books as the first two being about the ascension and the next two about the reign. I’m a solid pantser. I sold the original book on proposal. I had a synopsis and 50 pages written for the first book and a synopsis for the second book that contained everything I thought book two would be about, which is to say I had basically nothing for book two. If I found that synopsis it would probably reveal that nothing I said was going to be in book two actually appeared in book two. I think I said there would be daemons. There are no daemons. Nor is there any kind of series bible. When I write in book four that someone’s eyes are blue, I have to flip through the previous books to make sure that’s true. I do spend time thinking about the rules of the fantasy world I’m going to create. Is there magic? What kind of technology do they have? But after those things are established, I just turn my characters loose in the landscape and I learn things about their island the same time they do.

What was your biggest surprise?

I didn’t know who was going to win until the second book, five chapters before she did win. Even in the final book [Five Dark Fates], the final battle scene, I was not sure how that was going to end. I was having the adventure right alongside my characters. It’s amazing that somehow in the earlier books I managed to foreshadow things that I myself did not know at that point were going to happen! I’m not sure how I did that.

Does fan response shape the series in any way?

I read all of it and I read reviews but I don’t think any of that has much influence on the story. The story’s the boss. When I’m writing, I’m thinking about the characters. I’m pleasing no one but the story.

Were you thrilled to type “The End,” or sad?

Sad. Definitely sad. I remember doing the last event on the tour and thinking, ‘This is it.’ I was actually trying to be funny and upbeat at that last event but I was feeling depressed. I do have other books in the pipeline but I really missed those girls.

What’s next?

A pivot away from fantasy. Sort of a speculative YA version of In Cold Blood loosely based on Charles Starkweather, who went on a murder spree in the heartland with a woman named Caril Ann Fugate in the 1950s. They were teenagers, 14 and 19. It’s a total gear shift for me but I’m loving it.

Marissa Meyer

Supernova (Feiwel and Friends), the conclusion to the Renegades Trilogy about superheroes and super villains, in love.

How long was this series in the making?

Well I remember I was on tour for Scarlet when I had the idea so that was 2013.

What was your original inspiration?

I was on tour, sitting in the back of a car on the way to a signing when we passed a construction site with a sign that I thought read “Coming Soon to this location: Hero School.” I totally nerded out. My imagination ran with that. What if there was a school for superheroes? There would have to be one for supervillains, too, right? And what if a boy from the school for superheroes fell in love with one of the girls from the school for supervillains? Later I saw the construction site sign again and it said something else entirely but the idea had already planted itself in my head: a love story between a superhero and a supervillain.

Do you write with an outline?

With Renegades, by the time I really got to work on it I was on such a crazy deadline that all I could do was just write it. There was not a whole lot of note-taking. I do keep lists and write a lot of notes to myself. When I wrote Lunar Chronicles, which was much more complex, with more characters and more subplots, I had stuff all over my dining room table including colored pieces from a board game. Each color represented a different character which helped me make sure I wasn’t forgetting anybody. And part of my process is that whenever I’m finishing up a book in a series I stop and reread the previous book just to make sure I haven’t forgotten anything. I did have one character in Renegades whose hairstyle changed dramatically between books and I didn’t catch it. That one slipped through.

Any surprises in the writing/editing process—unexpected plot turns or character developments?

I almost feel like the entire third book was a surprise to me. There was a villain whose origin story didn’t come to me until halfway through book two but when I figured out where they came from and how it related to the other characters I was like, ‘Oh, yes.’ It pulled together all of these strings that I almost couldn’t believe I had come up with. It must have been brewing in my subconscious for a while.

Does fan response to the first book(s) shape subsequent books?

Well, for starters, I don’t read reviews. And I’ve always had really wonderful reactions from fans. It’s really rare that, in person, someone will question or criticize something from the books but when it does happen, I wonder if they missed what I was going for or if I didn’t really convey what I was hoping to. But there’s no controlling that so I try not to dwell on it too much.

Worst moment?

With Renegades, I had been working on it for years and had been through multiple drafts and multiple scenarios and plots and subplots and finally I sent it to my editor and when she sent me her editorial letter and I saw how much work it still needed, I had a complete breakdown. I was literally thinking ‘I hate this book.’ I called my agent and told her we should cancel this book and I’ll move on to something else.

What did you do to get back on track?

Lots of tactics. For Renegades, the first book in particular, I have a whiteboard in my office and I drew a little graph for myself with little boxes, and every 1,000 words I was allowed to check off a box towards this goal of finishing. I got a lot of motivation out of checking off those boxes.

How does it feel to leave your fantasy world — how hard has it been?

Well, the last book only came out in November so it’s barely over. With Lunar Chronicles, I remember feeling complete relief not only that I’d done it but that I could move on. It was only after a period that I started reminiscing about the characters. Right now with Renegades I’m happy to have put it to bed but it would not surprise me if in another month or so I am missing them again.

What’s next?

My new novel is coming out next November. It’s about a girl who develops the ability to produce instant karma—and that’s the title, Instant Karma. It’s not a trilogy but it’s going to be part of a series, more like companion novels. It’s been so fun.

Neal Shusterman

The Toll (S&S), finale to Arc of the Scythe trilogy about a perfect world in which teens must learn the “art” of killing in order to keep the population under control.

How long in the making?

Since I began, four years.

You have written lots of trilogies. Is it getting easier?

It never gets easier. If it was, I’d be doing something wrong. As a writer, it’s always important to do something to challenge yourself, get to the edge of your own creativity.

Original inspiration?

When I finished Unwind, I knew the last thing I wanted to do was write another dystopian series, so I decided to write a story about a world in which everything has gone right. What if all our best-case scenarios came true? I wanted to do something original that took place in a world where something has gone wrong and teens have to fix it. It definitely had something to do with what was going on in my life at the time the story came to me. My mother had just passed away after we had to make the decision to take her off the feeding tubes that had been keeping her alive. I was thinking about the people whose job it is to, with compassion, let people pass on.

Was there a moment where you thought ‘this just isn’t working?’

There are multiple moments like that in every book where you don’t know whether it’s actually going to come together. You have to work your way through the panic and remind yourself that you always do and it’s usually well worth the wait. The path out of the weeds can be quite spectacular. That’s the exciting part.

How was it outlining and juggling plot threads across multiple volumes?

My process is color-coded everything. I work the story out in my head as much as I possibly can before I start writing and when my head can’t hold any more I start writing on colored index cards. Each color represents a character or a plot thread. Usually, I have so many they cover my entire floor. When I have them ordered and organized, I transfer all that information into a color-coded spreadsheet. I spread them out and refer back constantly. It’s like a barometer for the story. If I have too much purple I know I need to go back to green for a while. If I’m missing an entire color for 100 pages I know I haven’t invested enough in one of the characters’ story.

Any surprises in the writing/editing process—unexpected plot turns or character developments?

Plenty. Characters do things that surprise me all the time, which is why even though I refer to the outline I don’t ignore what the characters are telling me. If I stick too close to the outline I miss those surprises. I have to leave the story open enough so that it becomes better than the idea I had to begin with. That’s really fun—when you come up with something even better because you were open to that possibility.

What’s the most outrageous thing you’ve done to get unstuck?

I was in Europe and I had a week between events so we were touring around. I was in Rome, at the Forum, sitting on a column and I just got the idea to take out my notebook and start writing. I got all this work done! So, next, I was at the Coliseum and I tried the same thing and I got a lot of work done there, too. Then we went to the Vatican, and the Sistine Chapel is the very last thing on the tour. They save that for the end and you’re supposed to take a look and keep moving, but there were benches so I thought, ‘How long can one sit in the Sistine Chapel and write?’ I sat there for two hours! No one ever kicked me out.

Does fan response play a role in how the series develops?

All the time. I read the reviews on Goodreads and Amazon. What I love is when someone quotes something that I have written. The idea that something I wrote might be quotable really tickles me. And we’re publishing a collection of stories from within the Scythe world, which will give fans some of the stories they asked for but which I couldn’t work into the series itself—like, do pets live forever, and can they be brought back to life? So many fans I have met on tour have asked that.

How hard has it been now that you’ve finished?

It's always very thrilling to type ‘the end,’ and I don’t type ‘the end’ until I’m really done and made all my personal revisions. But when I hover my hand over that ‘send’ button, that is very momentous.

What’s next?

I have several books in process, including one that I’ve been working on for a long time that I had to push back to finish this series, and a number of others that I’ve had partially done for a couple of years now. It’s enough to keep me busy for at least the next several years.