Mark Desvaux and Mark Stay—the coauthors of the comical sci-fi novel Back to Reality, about a mother who gets a life reboot by time-traveling to the 1990s—have done their homework so aspiring authors don’t have to. They have known one another since they were teenagers growing up in Surrey, England, and are both men of many hats. Stay works with Orion Publishing Group in the U.K. and is also a screenwriter. He cowrote the 2015 film Robot Overlords, which stars Gillian Anderson and Ben Kingsley. Desvaux lives on Vancouver Island, British Columbia, where he writes nonfiction under the name Mark Oliver, works as a life coach, and plays in a band named Urban Myth Club.

After Stay wrote the novelization for Robot Overlords, Desvaux gave his longtime friend and fellow writer a call. “I was blown away with what he had achieved,” he says. “I got in touch and uttered the fateful words: ‘I’ve always wanted to write a novel, but never got beyond 20,000 words.’ ” Stay was eager to write more prose as well, so they decided to collaborate on a book. Not just any book—a bestseller. And what better way to write a bestseller than to talk to the bestsellers themselves?

And so the Bestseller Experiment podcast was born. Over the course of a year, beginning with the first episode in October 2016, the two interviewed bestselling authors (with combined sales of over 100 million copies), who offered their advice. Stay’s ties to publishing proved helpful: “I’ve worked in bookselling and publishing for 25 years, and it turns out I know a few people. And I’m very persistent.” He adds that getting actor Bryan Cranston on the show to talk about his memoir, A Life in Parts, was a turning point. “It was an incredible interview that went viral,” Stay says. “If you heard Cranston say he would leave the U.S.A. if Trump got in, he said that on our show first!”

The podcast also gave Desvaux and Stay the kick in the pants they needed to follow through. “Believe me, there’s nothing like a public declaration of a deadline to get your fingers typing,” Stay says. He also came up with a way to further stoke the fire: by inviting other writers to join them in the experiment. “I figured at least one listener out there would have a half-written book on their laptop that would beat us to it, and we’ve been delighted to see so many listeners finish and publish their own novels,” he says.

Desvaux and Stay began their writing process by focusing on their shared passions: “Before we wrote a single word, we filled out a huge spreadsheet with all the things we loved, just to see what kind of crossover there was,” Desvaux says. They kept coming back to their shared love for Douglas Adams’s The Hitchhiker’s Guide to the Galaxy, Back to the Future, and rock music.

After creating an outline, Stay wrote drafts and Desvaux revised, a process that sometimes led to debate, but ultimately resulted in a book “about family, second chances, mothers and daughters, living your dreams, time travel and rock ’n’ roll... and there’s a funny bit with a cow,” Desvaux says.

“We’re both over the moon with the finished book,” Stay says. “I’m very proud of what we’ve achieved.”

Next they turned to promotion. “It began with the podcast,” Stay says. “If we could convert listeners into readers, then we knew we stood a good chance of selling a few copies on launch.” Social media channels came next. Their efforts paid off: by the end of the novel’s publication day, it had earned a bestseller flag on Amazon in the U.K. and U.S., also reaching the top spot on six Kindle bestseller lists. Desvaux and Stay also published Vault of Gold, a free e-book with writerly advice from the podcast.

The most common advice they heard from fellow authors? “Write every day,” Desvaux says. “If you can’t write every day, then be thinking about your story every day.”

Stay adds: “There are no shortcuts. For a book to connect with people, it has to come from a truthful place, and that can be the hardest thing of all.”