Sure, author Cassandra Clare is human—which makes her a “mundane” in the language of her young adult urban-fantasy novels. But she is hardly ordinary.

The former Hollywood Reporter writer boasts an impressive 24 million books in print worldwide, more than 150,000 Facebook “likes,” and close to 170,000 Twitter followers. With an enthusiasm reminiscent of the energetic demon-hunters (called Shadowhunters) in her novels, those loyal fans are helping to promote the highly anticipated August 21 big-screen release of The Mortal Instruments: City of Bones, based on her 2007 debut.

Unique Features optioned City of Bones in 2009 and teamed up with Constantin Film for the production. Clare gave her blessing as screenwriter Jessica Postigo and director Harald Zwart compressed the 485-page book into a two-hour movie. “It has been a pleasure for everyone and very easy for the filmmakers to have her so close to the process,” said Zwart, who also directed 2010’s The Karate Kid. “Cassandra Clare writes wonderfully visually. It’s a director’s dream to get ahold of a book like that.”

Some sticklers have quibbled (vociferously, online) that a few of the actors don’t quite match their book descriptions. For example, actress Lily Collins, who is 24, five-foot-five, and a straight-haired brunette with hazel eyes, plays main character Clary Fray—who in City of Bones is turning 16, just over five feet tall, and a curly-haired redhead with green eyes. “You go for the best performance and the best type,” said Zwart. “I’m hoping that the purists will at least appreciate that we kept the spirit of the characters and the intentions of the book.”

Clare, who saw a rough cut in March and the finished version on July 22, believes that will be the case. She watched, via computer, the auditions for everyone except Collins and “absolutely” voted for James Campbell Bower to play the male lead, Jace Wayland. “He’s gotten older and hotter!” she said. (Fans of the movie’s YouTube trailers—the first one boasts nearly 3.4 million views—largely agree. One calls Bower “purrrfecttt.”) Last fall, Clare spent two and a half weeks visiting the City of Bones set in Toronto. While there, she worked on revisions to her manuscript for Clockwork Princess, the final title in her Infernal Devices trilogy, a companion series set in the Victorian era that also has been optioned for film by the Mortal Instruments team. The author is no stranger to the movie industry—her grandfather produced the original Tales from the Crypt films and let her tag along on set—and she makes a cameo in City of Bones, as a cat demon in a party scene.

Following in the footsteps of previous page-to-screen blockbusters, Sony, the film’s distributor and marketer, is promoting a number of tie-ins. “We’d love for it to turn into the kind of franchise that Twilight and Harry Potter are,” said Gregory Economos, senior v-p of global consumer products for Sony Pictures. Hot Topic is selling movie-related apparel, jewelry, makeup, and temporary tattoos. Simon & Schuster imprint McElderry Books is releasing three tie-in books: Shadowhunter’s Guide, with photos of the film characters; City of Bones: The Official Illustrated Movie Companion, which includes interviews with Clare, Collins, and Zwart; and the original novel with new cover art from the film. Meanwhile, since January, S&S has been sending booksellers reading-group guides, tattoos, and car window clings that read “Protected by Shadowhunters.” And at BEA, the publisher threw a blowout party for Clare at the neo-Gothic Angel Orensanz Center on Manhattan’s Lower East Side—complete with henna-tattoo artists and a tarot-card reader, and showed a five-minute clip from the film.

The well-read author, whose stories mix romance and teen repartee with lines from Shakespeare and Blake, is looking far beyond the forthcoming movie. Currently she is putting the finishing touches on City of Heavenly Fire, her sixth and final Mortal Instruments title, due out May 2014. (On the City of Bones set, actors approached her to ask whether they were going to die in book six, but she replied, “’I’m not going to tell you!’ ”) Mortal Instruments: City of Ashes, based on the second book in the series, will begin filming this fall, and a director for Clockwork Angel, first of the Infernal Devices books, is expected to be announced soon. Clare and her husband, Joshua Lewis, are collaborating on The Shadowhunter’s Codex, billed as a “training manual,” out October 2013. And, along with writer pals Maureen Johnson and Sarah Rees Brennan, she’s writing 10 e-story installments about fan-favorite warlock Magnus Bane (a centuries-old, youthful-looking immortal), which will be published as a print collection in September 2014.

An Author’s Origin Story

After a stint running the children’s section at a Barnes and Noble in Los Angeles (“that was one of the things that got me hooked on kids’ books and YA”), Clare worked as a journalist, first in L.A. and then in New York as a freelancer, writing under her given name, Judith Rumelt. Meanwhile, she was writing Lord of the Rings and Harry Potter fan fiction as Cassandra Claire (she dropped the “i” and retired the fanfic name when she went pro). A visit to a friend’s workplace—a tattoo parlor—about a dozen years ago sparked the idea for the Mortal Instruments novels, whose half-angel, half-human characters get powers from runes etched into their skin. Around the same time, she began participating in a children’s book–writing online discussion group, where she met her now-husband. She picked up evening work as a freelance copyeditor for Star and the National Enquirer, and worked on City of Bones during the day. That book sold in 2005; by 2009 she was writing fantasy fiction fulltime.

Clare, born in Iran to American parents, spent much of her childhood moving with her family from country to country (her father, a professor of international business strategy, was posted to various universities). Her parents divorced when she was 19; both later remarried. “Luke, who is Clary’s sort-of stepfather, is based on my own stepfather,” she said. “There are so many children of divorced parents. I was trying to get across the message that it’s not so much blood as the people who love you and take care of you.”

But make no mistake: Clare is not Clary. “She’s an artist. I’m terrible at art. I’m much more cautious.” That said, Clare and Clary do share some similarities. “When I was growing up, I always had all these books about magical heroines, and they would always have blonde hair or black hair,” she explained. “As a red-headed, freckled girl, I felt like we were unrepresented. I wrote about the kind of girl I wanted to read about.”

Clearly, her efforts are resonating with readers. In July 2012, a fan-led cover reveal of Clockwork Princess drew more than 30,000 tweets in two hours. In March 2013, a similar campaign to uncover the book’s first chapter garnered more than 560,000 tweets in 27 hours. “We try to step it up with every Cassie book,” says Anne Zafian, v-p and deputy publisher of children’s books at S&S. “That’s not easy.”

The author is doing her part to keep the momentum going. She writes from 1 to 6 p.m. in a coffee shop a few miles from her home outside Amherst, Mass., often with other author friends, including Holly Black. “You need somebody keeping an eye on you so you’re not online shopping,” Clare explained. Black is more than just a watchdog: the pair are co-writing a five-book fantasy series, called The Magisterium; Scholastic will publish the first installment, The Iron Trial, in 2014.

Clare continues to work closely with editor Karen Wojtyla, who acquired the Mortal Instruments series back in 2005. (“I think it took until about page five, and I knew I wanted to publish it,” said Wojtyla.) The veteran editor sends changes the old-fashioned way—with pencil comments in the margin and an overall editorial letter. “That manuscript can’t ever be lost,” Clare said. “I rewrite scenes on the paper.” For City of Bones, she used scissors, tape, and glue to revise. (“Karen was like, ‘What have you done?!’ ”)

With the impending Mortal Instruments finale, Clare and Wojtyla are gearing up for two new series: the Dark Artifices trilogy, which follows Shadowhunters in present-day Los Angeles, and another, as yet untitled, that will follow further adventures of the Victorian Shadowhunters—“with a new cast of characters but with appearances from people we might know,” said Wojtyla.

And this month, between movie events and writing sessions, Clare plans to get her first tattoo, of the rune that makes the wearer afraid of nothing. Given Goodreads comments like this one, from a fan not so patiently awaiting next year’s release of City of Heavenly Fire —“If I die before this book comes out, I’ll come back and haunt her forever”—the extra protection sounds prudent.

This article has been corrected. An earlier version of this article incorrectly stated Cassandra Clare's husband's first name as Jason. It is Joshua.

More Coming Attractions

Percy Jackson: Sea of Monsters

The second film in Rick Riordan’s Percy Jackson saga (2006) catches up with the son of Poseidon and fellow demigods as they train to battle the titular mythological beasts and to retrieve the Golden Fleece. To date, more than 33 million books (across the Percy Jackson & the Olympians, Kane Chronicles, and Heroes of Olympus series, all from Hyperion) are in print in the U.S. The film, from 1492 Pictures/Sunswept Entertainment and 20th Century Fox, arrives in theaters August 7.

Ender’s Game

Amid recent controversy surrounding author Orson Scott Card’s anti-gay views, the film adaptation of his sci-fi cult classic Ender’s Game (Tor, 1985) is slated for a big-screen release on November 1 (albeit with Lionsgate Entertainment publically distancing itself from the author’s statements). The movie, about a boy who is plucked from Earth to enroll at Battle School in space, stars Asa Butterfield and Harrison Ford.

The Book Thief

Brian Percival directs this screen adaptation of Markus Zusak’s Printz Honor book (Knopf, 2006). The bestselling YA novel, which is narrated by Death and takes place in Nazi Germany, has enjoyed significant adult crossover appeal. The Fox 2000 film stars Geoffrey Rush and Emily Watson; it opens November 15.

The Hunger Games: Catching Fire

One of the most anticipated sequels of 2013, the second installment in Suzanne Collins’s Hunger Games trilogy (Scholastic, 2009) sees Katniss (Jennifer Lawrence) and Peeta (Josh Hutcherson) targeted by the Capital because their defiant win has incited rebellion throughout the Districts. The Lionsgate film launches November 22.

The Hobbit: The Desolation of Smaug

Jackson’s second film based on Tolkien’s preamble to the Lord of the Rings series follows Bilbo Baggins (Martin Freeman), Gandalf (Ian McKellen), Thorin Oakenshield (Richard Armitage) and the rest of the Middle-earth crew on a journey to defeat the dragon Smaug. The New Line Cinema production premieres December 13.

The Maze Runner

Dashner’s 2009 book is the first in a dystopian series from Delacorte that centers on a group of boys locked inside an enormous labyrinth. The original trilogy plus a prequel, The Kill Order (2012), have sold a combined 2.4 million copies worldwide. Director Wes Ball’s film adaptation stars Dylan O’Brien, Will Poulter, and Kaya Scodelario, and will be out February 14.

Vampire Academy: Blood Sisters

The first film based on Richelle Mead’s six-book paranormal romance series (Razorbill, 2007) introduces Rose Hathaway (played by Zoey Deutch), a Dhampir, or the child of a vampire and a human, whose destiny is to protect gentle, mortal vampires called the Moroifrom their immortal—and malevolent—ancestors, the Strigoi. Across the series, the books have sold more than eight million copies worldwide. Release date February 14.


Veronica Roth’s first novel in a sci-fi trilogy (HarperCollins/Tegen, 2011) takes place in a dystopian Chicago, where society is divided into rigid factions based on personality. Shailene Woodley stars as Beatrice ‘Tris’ Prior, who learns that she is a “divergent,” and doesn’t conform to any of the factions. The Summit Entertainment film, due out March 21, 2014, also stars Theo James as Beatrice’s love interest, Tobias ‘Four’ Eaton, and Kate Winslet as Jeanine Matthews. The series has sold well into seven figures and has spawned a plethora of fan sites. The third book in the series, Allegiant, will be out October 22.—Matia Burnett