After creating a $3.5 billion franchise with a string of high-profile filmmakers—Chris Columbus, Alfonso Cuarón and Mike Newell—Warner Bros. hired David Yates to take the reins for "Harry Potter and the Order of the Phoenix," which will be released next summer.

"He's one of the most exciting directors coming out of this country at the moment," says longtime "Potter" producer David Heyman. Fair enough. But what's a guy who makes gritty, hyperreal socially conscious films doing in the "Harry Potter" universe? "Well," Heyman says, "this movie is bit of a revolution."

In person, Yates, 43, seems like anything but a colorful individualist. He's so unassuming that it's hard to find him on set, even when he's only a few feet away. It's only in private conversation, when his knees start knifing up and down and his words start coming faster, that you sense the red blood pumping beneath that beige exterior. "I'm having the time of my life," he says. "It's like being at filmmaking gym. You're working every single muscle as a storyteller.

These films are full of comedy, adventure and a bit of thrills. It's terrific." Yates has pushed all the actors, in particular Daniel Radcliffe, who plays Harry, to deepen their performances this time around. "I've stretched Dan quite a bit. He's a very intuitive person, very bright, quite sensitive," he says. "I'm just helping him wake those things up. You can see his determination and ambition, and he can switch things on a sixpence, so I can't wait for people to see what he's achieving."

Yates does a lot of rehearsal before he shoots a scene, a rarity on major studio films. "It takes as long as it takes," he says. "The most important thing on screen is the actors. If the performance isn't real, that million-dollar special-effects shot behind the actor doesn't count for anything." And if he pulls off that piece of magic, his days of anonymity are numbered.