Polly Shulman shares the challenges of writing her time-travel novel, The Wells Bequest, a story full of fantastic objects from popular science fiction stories and packed with fascinating time-travelling conundrums!

I thought the hardest part of writing a time-travel novel would be getting the historical details right. I was wrong. The hardest part was dealing with the paradoxes.

In The Wells Bequest, my characters work at a very unusual library—one that lends out not books, but objects. Want to try playing a tuba or see how you would look in Marie Antoinette’s second-best wig? You can borrow them from the New York Circulating Material Repository. Hidden in the repository’s basement are several Special Collections. One houses working, magical objects from fairy tales (this was the subject of my previous novel, The Grimm Legacy). The Wells Bequest involves the repository’s collection of working gadgets straight out of science fiction: starships, shrink rays, invisibility potions, and so on. But the star of the story is the time machine from H.G. Wells’ classic novel. My characters use it to visit Nikola Tesla—the world’s greatest (real-life) mad scientist—in his New York City lab in 1895, on the eve of the fire that destroyed it.

Getting the historical details right was very important to me. I searched 19^th century newspapers for stories about Tesla and his contemporaries, read biographies, hunted up old restaurant menus, pored over photos and train schedules, and stalked through Tesla’s neighbourhood with antique maps to see how the streets had changed. I even interviewed a transit historian to find out how people got around town back then. What were the fares for horse-drawn omnibuses? How about trolleys? Where did you buy a ticket for a ride on the elevated railroads, and did the ticket clerk punch it and give it back to you or just keep it? Even if nobody else ever noticed, I wanted to get things right!

But all that research was a walk in the park compared to keeping the time-travel paradoxes straight. The most famous one is the Grandfather Paradox: Suppose you use a time machine to travel back a few decades and kill your grandfather before he meets your grandmother. Then your mother will never be born, so you yourself will never be born, so you will never use a time machine to travel back in time and kill your grandfather. That means your mother will be born after all, and so will you, which means you will be able to use that time machine after all and kill Grandad, so you won’t be born, so you will be, so you won’t be…

H. G. Wells’ novel was no help with this particular paradox. His character uses the machine to go forward in time, not backwards. Going forward in time doesn’t raise nearly as many difficulties—after all, we’re all travelling forward in time all the time!

Related puzzles kept popping up all over my story, driving my editor crazy. We would have dialogues like this:

My editor: Wait! How could Leo and Jaya find the time machine in London in Chapter 13? I thought it was in the repository in New York the whole time! Is it a different time machine?

Me: No, it’s the same one. It’s just on an earlier trip. It’s crossing paths with itself.

My editor: How can it be an earlier trip, when they’re both there now?

Me: Time machines can be two places at once—that’s what time machines do.

In the end, all we could do was laugh—which is what I hope everyone will do when they read The Wells Bequest.

The Wells Bequest is out now.

Polly Shulman has written about edible jellyfish, Egyptian tombs, infinity, blind dates, books, brains, centenarians, circuses, and cinematic versions of Jane Austen novels, for The New York Times, Salon, and many other publications. She edits news stories about fossils, meteors, the ocean, the weather, and the planets for Science magazine.

Polly collects Victorian jewellery, puts cayenne pepper in her chocolate cookies, and reads forgotten books with frontispieces.

She grew up in New York City, where she lives with her husband and their parakeet, Olive.