ow many books are there in The Infernal Devices trilogy?

There are three. The title of the trilogy itself is The Infernal Devices: the first book is called The Clockwork Angel, the second The Clockwork Prince, the third, the Clockwork Princess.

When will The Clockwork Angel be out?

September 7, 2010.

What's The Infernal Devices about?

The Infernal Devices is a series of prequels to The Mortal Instruments series, set in 19th century London. The story concerns 16-year-old orphan Tessa Gray, whose quiet life is thrown into turmoil when her older brother Nathaniel suddenly vanishes, leaving her alone. Her search for him leads her into Victorian-era London’s dangerous supernatural underworld, where warlocks throw masked balls for half-demon Downworlders. When Tessa discovers that she herself is a Downworlder, she must come to trust her natural enemies, the demon-killing Shadowhunters, if she ever wants to learn to control her powers and find her brother. Torn between the beautiful Will, a Shadowhunter who isn’t what he seems, and the devoted Jem, whose own deadly secret is slowly destroying him, Tessa must draw on all her strength to save her brother and keep herself alive in this deadly new world.

How does The Infernal Devices tie in with The Mortal Instruments? Will we see some of the same characters in both?

As you meet new characters and encounter new settings in the Infernal Devices, you’ll start recognizing the family names of characters from the Mortal Instruments books — names like Herondale, and Lightwood, and Wayland. And characters who have either been in the MI series, like Magnus Bane, or who have just been mentioned and not seen — like Camille — will make appearances. There are even questions answered in the ID series about stories or objects in the Mortal Instruments, like the origin of Isabelle’s ruby necklace. (Or course if you read the books in the other order, you’ll have the opposite experience. But neither series spoils the other; they just complement each other.) And vice versa, Tessa shows up in City of Glass, though so briefly you might miss her if you don’t know what you’re looking for.

Will there be romance in The Infernal Devices like there is in The Mortal Instruments?

I get this question all the time, and I don’t know why! It totally puzzles me, but it’s clearly something people want to know. Yes, there will be romance in the series. I love writing romance. All my books are, in some sense or another, love stories. And complicated, passionate, maybe-it-will-work-out-maybe-it-won’t romance is my favorite kind. While Tessa clearly is not going to have the exact same romantic problems that Clary did, I think the story of her romantic life is just as interesting.

Where did you get the idea for The Infernal Devices?

I actually got the idea for The Infernal Devices before I got the idea for The Mortal Instruments. It started with a strong mental image: the image of a Victorian-era girl and a boy standing on a bridge in London while creepy-looking mechanical monsters came after them. I had always loved the Victorian age in London, and always wanted to write a story set there; I knew I wanted to include steampunk elements, and I knew I wanted there to be a love story. I knew I also wanted to bring in fantasy and magical elements, and that the main character of the story would be a girl with an unusual power — the power to change her appearance and disguise herself as anyone. The idea for the Mortal Instruments came later and I decided to write it first, basically on the theory that it would be easier to sell a contemporary fantasy than a historical one. (Hey, you’ve got to get your foot in the door somehow.) While I was writing the Mortal Instruments, the story of the Devices remained in the back of my head, nagging at me, and I would occasionally make notes about the plot and characters so I wouldn’t forget about them. As I built the world of the MI series, I realized I wanted Devices to take place in the same world, and that the mythology of one could be easily folded into the story of the other. I started drawing family trees, connecting the characters in one series to the characters in the next, and was surprised at how quickly the connections came.

Wait, what’s “steampunk”?

Steampunk is very hard to define. There are a number of definitions to be found here, including this one from Tinker Girl at Brass Goggles, that I like: “Steampunk is a genre of fiction set somewhere in the 1800’s during the Victorian Era. The fictional part comes in that technology has gone a bit skewed - though the exact methods vary, generally steam-powered devices that would have been impossible or unfeasible at the time are found to exist. Examples include steam-robots, flying castles, under-water bases, moon rockets, time machines etc.”

Obviously, this doesn’t really describe my Clockwork series, which is set in our recognizable historical past, not an alternate version of it. But I love the aesthetic of steampunk and tried to work it in in small ways, most notably in the existence of the mechanical human-seeming automatons that figure significantly into the plot, and in Henry's endless inventing of all sorts of mechanical devices that really didn’t exist in the Victorian Era — but hey, there weren’t really vampires and werewolves in London, either.

I also recommend reading this excellent essay by Cherie Priest.

What kind of research did you do when writing these books?

For six months, I read only books that were written during the Victorian period, or set in the Victorian period. I went to London and walked all the routes I expected my characters to walk — taking into account the way the geography has changed, I did the best I could! I took photos for reference, and went to the Guildhall Library to study maps and records. I read a ton of books that concentrated on one tiny specific historical detail — like “Carriages at Eight!” by Frank Huggett. And I still wish I had many more months to do more!

What are the "Infernal Devices"?

“Captain,” said I, just as though I entertained no doubt of the authenticity of Edgar Poe’s romance, “is it not the case that all these men perished, some in the attack on the schooner, the others by the infernal device of the natives of Tsalal? — An Antarctic Mystery, Jules Verne, 1897

You'll have to read the books to find out, but as they deal with all sorts of monstrous mechanical devices, I think it won't be too hard to figure out. "Infernal Device" is a Victorian-era term that means a sort of deadly device or bomb. The term is something of a steampunk idiom, most notably appearing as the title of KW Jeter's classic book Infernal Devices.