David Mitchell has recently realized something very important about his books—they’re not really novels. 

This may sound like an odd insight coming from a man whose five previous books have all been international best-sellers and have each been awarded or nominated for major literary prizes. Yet Mitchell, much like the characters he brings to life, can’t help but explore the mysteries around him—even when those mysteries are his own writing habits.

“I am a writer of novellas, I think. My ‘novels’ are carefully tucked and tailed and joined sequences of novellas,” Mitchell says. “The payback is potentially a multipart novel that hopefully can feel quite original. That’s something I’ve discovered fairly recently.”

This originality has earned Mitchell rapturous critical acclaim and legions of devoted readers around the world. Each book pushes the boundaries of novelistic structure into new and exciting territory. Whether it’s Cloud Atlas, where each section is left unfinished, only to be completed by a later section, or number9dream, whose narrative zigzags around multiple points of view and in and out of dream sequences, Mitchell is known for following his own rules and exploring his own interests.

“I’m interested in what we could call literary propinquity, or next-ness,” Mitchell says. “Put one thing next to another, and it’s a third thing. It’s not there, but it’s in the fact that they’re next to each other. You get this on expertly compiled playlists, don’t you? The two songs make this third thing when they transfer from one to another. It’s all in the flow, in the sequence.”

The Bone Clocks, Mitchell’s latest novel (if we can still call them that), stretches over 60 years and includes dozens of characters on multiple continents. At its heart is a metaphysical mystery surrounding the afterlife and the great, unanswerable question: What happens after we die?

In this book, Mitchell has provided the answers and the cosmology that were only hinted at in his previous work. Holly Sykes, the main character and narrator of two of the six sections, is caught between two powerful forces that will shape her life and her family for decades. On one side is The Anchorites, a group of powerful, potentially immortal Carnivores, who view human beings as merely the food they need to stay alive. The Anchorites are opposed by The Horologists, who are reincarnated into successive lives without human sacrifices.

The mystery grips the reader from the start, but so do the characters. The success of The Bone Clocks lies in Mitchell’s ability to combine the metaphysical adventure with characters the reader comes to deeply care about. Yet for Mitchell, this combination isn’t worthy of any special distinction. It’s all part of a day’s work.

“My job is to do both,” Mitchell says. “A book that’s solely [metaphysical] can be didactic, but a book without ideas is like a diet without vitamin C. I like a book that has motion and people I care about.”

Even when she’s not the narrator, Holly remains the emotional core The Bone Clocks orbits. She stumbles into this battle between good and evil in the book’s first section, which is set in 1984 when Holly is 15 years old. In the final segment, set in 2043, Holly is close to death but still connected to the Horologists. In between are four novellas narrated by different characters, whose lives intersect with Holly’s in important, life-changing ways.

Sometimes the connections to Holly’s life come late in a section, and it’s a thrill when Holly resurfaces. The second novella, for example, is narrated by Hugo Lamb, a Cambridge student who’s slowly building a secret life for himself by cheating his friends and concocting grand, harmful lies. Hugo meets Holly at a Swiss ski resort and is immediately drawn to her.

“Holly herself is strong glue, hopefully,” Mitchell says. “And she becomes a personification of each of the novella’s themes, in a way. In the second part, Holly is a lover, and that section, among other things, is about that stage in your life when you have lovers, not husbands or wives.”

Each novella moves the battle between the Anchorites and the Horologists closer to the final showdown. The proximity, or propinquity, that Mitchell values so much comes to the fore as the reader follows Holly’s growth by inevitably comparing her and her relationships to the earlier sections.

This proximity drives all of his work, Mitchell acknowledges. Characters from each of his previous novels appear in The Bone Clocks. Hugo Lamb has a small role in Black Swan Green, Dr. Marinus from The Thousand Autumns of Jacob de Zoet is a major character here, and multiple cameos from Cloud Atlas characters dot the book.

These cameos and references will be satisfying to Mitchell’s readers but shouldn’t mystify people coming to Mitchell for the first time. “Each of my books is and must be a stand-alone novel in its own right—not a prequel or a sequel,” Mitchell says. “But each of them are chapters in the ‘uberbook,’ which is my life’s work, and which I’ll keep cracking on until I die.”

It might even be too constricting to call Mitchell’s oeuvre an “uberbook” because his work is branching into other forms. Marinus appears in the opera Sunken Garden by Michel van der Aa, with a libretto by Mitchell. In July, Mitchell wrote “The Right Sort,” a short story in tweets. Experimenting with new structures and forms keeps Mitchell “omnivorous,” he says. “I hope that’s the antidote to repetition.”

Mitchell is already at work on his next projects. First, he’s going to expand “The Right Sort” into a stand-alone (so he claims) novella. After that, he’s returning to a character from Cloud Atlas in a book set in London and “a little bit” in New York in the years between 1967 and 1970. “We’ll meet young Timothy Cavendish then,” he says.

“I’m quite excited by the artistic possibilities inherent in all this,” Mitchell says. “I accept my fate as the writer of novellas who needs to find ways to turn novellas into novels. I accept my fate quite gladly.”

Richard Z. Santos is a writer and teacher living in Austin. His work has appeared in The Texas Observer, Culture Strike, Nimrod, The Rumpus, the San Antonio Express News and many more. He’s working on his first novel.