The audiobook has been undergoing a serious makeover. What used to be an inconvenient niche industry for the gung-ho (a six-CD jewel-case monstrosity, or worse, a giant box of cassettes!) has performed death-defying backflips around its wilting print counterparts in recent years. And it's only getting better: according to a survey conducted by the Audio Publishers Association last year, an already energetic market more than doubled its publication rate from 2012 to 2013, making for what's now estimated at a $1.3 billion industry. (70 percent of all sales are, of course, digital.)

And, as any good capitalist knows, with such a boom inevitably comes innovation. As production costs plummet and the economy perks up, the audio publishing industry has begun taking on a life of its own of late: re-formatting already published works is still its bread and butter, but now publishers are commissioning original material, and even experimenting with the form in ways that evoke radio plays of the early 20th century. There are audio-only novellas penned by well-known authors, ensemble performances, original scores—it would be difficult to find someone in the audiobook biz who would tell you this isn't the future of their medium. "Five years ago, my colleagues were still trying to explain what an audiobook was," Audible EVP and publisher Beth Anderson tells WIRED. "We don't have to explain that anymore. Now, we're still [adding books], but we're able to try all sorts of new material in addition to that."

Audible launched in the late 1990s, but in recent years the subscription audiobook service has begun commissioning more and more original stories, currently housing over 100 creative titles. Its latest get: a new story by young adult author Philip Pullman. The Collectors, out yesterday, is one of a handful of recent stories Pullman has written as companions to his classic His Dark Materials trilogy—and it's the first he's written exclusively for audio.

"[I liked] just the idea of writing for a voice," says Pullman, who was initially approached and subject-prompted by Audible for the project. (While some authors narrate their own stories, consummate Brit Bill Nighy does the honors for The Collectors.) "I wanted to tell a story of the sort that the great English writer of ghost stories M.R. James might have thought of. I’d never done exactly that before, and it was a challenge I enjoyed very much. "

It's not just major publishers who are able to explore new options. Last month, indie audiobook publisher Tantor released* My Life with Piper: From the Big House to the Small Screen*, an audio original written and narrated by Larry Smith, aka Piper's boyfriend from Orange is the New Black fame. Also published in December: Full Metal Jacket Diary, the audiobook adaptation of Full Metal Jacket star Matthew Modine's 2005 memoir. In 2012, Modine and producer Adam Rackoff released a fully crowdfunded "app-umentary" version of the book*,* which recounts Modine's experience filming Stanley Kubrick's iconic Vietnam War film, to coincide with the movie's 25th anniversary.

"When we started building the app [in 2011], we knew we wanted an audio element, so we recorded Matthew reading his entire diary," says Rackoff. "[Once we decided on an audiobook format,] we had to record new elements and create a more surrounding experience for the listener."

The resulting audiobook version (which also crowdfunded last spring) comes equipped with both an original score and high-quality sound effects. Even if you listened to it on a state-of-the-art home theater system, Rackoff says, the production would sound, well, like a military movie memoir.

Podcasts have already turned what a novelty into an exceptionally accessible medium—and just like longform audio journalism, literature stands to benefit from our newly open ears. "That out-loud form is really the oldest storytelling medium," says Audible's Anderson. "For us, it's a way to expand what our current listeners are getting and also bring in new types of listeners—people who think, 'I'm not so interested in listening to a 20-hour book, but I might be interested in something shorter, or multi-voiced.'"

Additionally, as Rackoff and Modine discovered, audio holds a fundamental benefit over app-based storytelling: an audience that isn't limited by owning the right device. "Outside of a physical book, audio is probably the most democratic way of sharing a story," Rackoff says. "We realized that an audiobook might be the best way to reach the largest number of fans that couldn't experience the iPad app—the great thing about audiobooks is that almost anyone can enjoy them." Multiple Full Metal Jacket fans serving in the armed forces—who might not have an iPad or the luxury of leafing through a giant metal-plated coffee table book—have written the pair to thank them for its production quality.

And as the form gets cheaper and cheaper—many voice actors, Anderson says, have set up mini-recording studios in their homes, recording, editing, and sending publishers finished audiobooks using just a laptop and a microphone—the bells and whistles will only get more elaborate. "We're not going to stray away from recording books," she says. "That'll still be a very, very important part of our business—but we'll be able to do more on top of that."