Young adult fiction, preferably with a dystopian or supernatural twist, is the literary genre causing most buzz among publishers and film scouts as they flock to this year’s London Book Fair.

Ever since “Harry Potter” burst out of the children’s section to become a four-quadrant phenomenon, and the “Twilight” series reached beyond its core crowd of teenage girls, everyone has been trying to spot the next youth franchise with the potential to cross the generation gap, on the page and on screen.

DreamWorks has pinned its hopes on Pittacus Lore’s teenage alien tale “I Am Number Four,” while Lionsgate is making a big bet on adapting Suzanne Collins’ post-apocalyptic “Hunger Games” trilogy.

The dystopian “Chaos Walking” trilogy by Patrick Ness, and his latest novel “A Monster Calls,” is attracting strong interest from Hollywood. But so far reps for Ness have resisted all approaches, knowing how hard it will be to get his complex metaphysical material right on the big screen.

“Young adult is indeed huge, but these novels do tend to be quite intense, quite challenging,” notes London-based literary scout Suzy Lucas.

Among recent movie deals, Scott Free has snapped up Glen Duncan’s “The Last Werewolf,” launched to publishers at last year’s London Book Fair, while Working Title has optioned “The History Keepers,” a planned trilogy of novels by Damien Dibben about a teenage boy travelling through time in search of his missing parents.

The new title making the biggest stir ahead of this year’s fair is Karen Thompson Walker’s debut novel “The Age of Miracles.” It sparked a multi-million-dollar bidding war among American and British publishers last month, and is sure to be tracked closely by film scouts. It’s an apocalyptic coming-of-age story about an 11-year-old girl in suburban California who wakes up one morning to find the world is starting to turn slower, with catastrophic consequences.

More on the London Book Fair:
Book Fair rises from the ashes