With the Twilight sequels currently filming, we're wondering which book series will be the next to hit the big screen.
Industry analysts were caught off-guard by Twilight , underestimating how screaming teenage girls can influence box office.
With studios clamouring to bite off a piece of the teen-lit action, book properties are being gobbled up faster than you can say 'Robert Pattinson'.
Here's the books we're tipping to be the next big crossover movie sensations...
Author: Justin Somper
The pitch: Grace and Connor are recently orphaned twins living in Australia. Not wishing to be taken into adoptive care, they set sail on their father’s boat.
When the boat sinks, the twins are rescued by two very different vessels; Connor by the pirate ship Diablo, Grace by the Vampirate ship Nocturne.
The pedigree: The Vampirates series has been in publication since 2005, and has built up a dedicated following.
In case you missed it - yes, 'Vampirates'. That's pirates who are also vampires.
Books in series: Four, plus one short story
Web presence: 35,100 hits on the Googles.
Big screen potential: Pirate vampires? Can we book our tickets now?
Next: Percy Jackson And The Olympians [page-break]
Percy Jackson And The Olympians
Author: Rick Riordan
The pitch: 12-year-old Percy Jackson discovers he's the son of Poseidon, and that the Gods of Greek Mythology are alive and well.
Monsters still exist too, and Percy must fight to survive while trying to stop a war between the Gods - a war in which he may be destined to play a role...
The pedigree: The series has stayed on the New York Times Best Seller list for the last 95 weeks.
The first book, The Lightning Thief, received much critical praise and was showered with awards on its release in 2005.
Books in series : Five
Web presence: 379,000 hits on Google.
Big screen potential: A film adaptation of The Lightning Thief is already in the works, directed by Chris Columbus and starring Pierce Brosnan.
Next: Vampire Academy [page-break]
Author: Richelle Mead
The pitch: Rose Hathaway, a half human/half vampire and best friend Lissa, a Princess of the Moroi vampires, are on the run from evil dead-soul monsters the Strigoi.
They are found by handsome guardian Dimitri, who brings them back to the Vampire Academy in Montana, and into the hands of the Strigoi...
The pedigree: The Vampire Academy series has boomed in popularity off the back of Twilight ’s success, with fans desperate for something else to sink their teeth into.
This smartly written and engaging series has sated the appetite for vampire stories, and become a success in its own right.
Books in series: Four.
Web presence: 183,000 Google hits.
Big-screen potential: No plans yet, but with Twilight raking in the pennies, it can’t be far off.
Next: Noughts & Crosses [page-break]
Noughts & Crosses
Author: Malorie Blackman
The pitch: The series is set in a fictional future dystopia, where people with black skin (Crosses) are dominant over those with white skin (Noughts).
Sephy, a Cross, and daughter of a prominent politician, falls in love with Callum, son of a cleaner. With their love forbidden, the pair meet in secret, but how long before they're found out?
The pedigree: The books have garnered many awards since the first instalment, Noughts & Crosses, was published in 2002.
The story tackles challenging interracial/cross-cultural themes - riffing on elements of Romeo & Juliet - and is set in a world with disturbing similarities to Apartheid-era South Africa, except in reverse.
Books in series: Four, plus one short story.
Web presence: 166,000 Googles.
Big screen potential: The book has already been adapted by the RSC, touring to positive reviews in 2008. In the right hands this has the potential to be massive.
Next: Artemis Fowl [page-break]
Author: Eoin Colfer
The pitch: 12-year-old boy, Artemis Fowl II, is an extremely intelligent and ruthless young criminal mastermind, who pursues riches through a variety of illegal schemes.
Believing he has confirmed the existence of fairies, Artemis gains possession of the Fairy Holy Book, which he plans to use to capture the vast reserves of fairy gold.
The pedigree: The author describes the series as "Die Hard with fairies".
The books have dominated bestseller lists across the world and have garnered several awards.
Books in series : Six.
Web presence: 116,000 Google hits.
Big-screen potential: Jim Sheridan, director of In America , was supposedly developing a script in 2008, but the project appears to be on hold.
Next: Power Of Five [page-break]
Power Of Five (The Gatekeepers)
Author: Anthony Horowitz
The pitch: The series focuses on five children: Matt, Pedro, Scott, Jamie, and Scarlett, a group of 14-year-olds destined to defeat mystical entities known as 'The Old Ones'.
The first book, 'Raven’s Gate', follows Matt, a petty thief, as he is sent to live in the small town of Lesser Mailing, where he uncovers a conspiracy to release a powerful 'Old One'.
The pedigree: The five children are introduced slowly over the series, with all five not featuring until the fourth book, Necropolis. Could be tricky for a film franchise - unless they can compress everything into one movie.
The fifth book has yet to be released, and Horowitz claims it make take years to finish.
Books in series : Four so far.
Web presence: 55,800 Googles.
Big-screen potential: The first book in Horowitz’ other series, the Alex Rider spy-novels, was adapted into the film Stormbreaker in 2006, although it was widely regarded as a disaster.
Next: Night World [page-break]
Author: LJ Smith
The pitch: The series takes place in a world similar to our own but vampires, witches, werewolves and shapeshifters live secretly among us.
The first book 'Secret Vampire' concerns a terminally ill girl whose best friend reveals himself as a vampire, and offers to break the rules to save her life.
The pedigree: The series was originally published in the '90s. The tenth book has been pushed back every year for the last eleven years.
The books were re-released last year, gaining a new audience in the wake of Twilight , and LJ Smith has announced she has nearly finished the final book.
Books in series: Nine so far, with the tenth supposedly out this summer.
Web presence: 96,900 Google hits.
Big-screen potential: It's Twilight Lite, and the producers would be looking to harness the power of those screaming teenage girls again...
Any young-adult books you'd like to see on the big screen? Let us know in the Comments.