Insomnia is the kind of movie you rarely see in summer: thoughtful, gripping and steeped in action that defines character. The fact that this superior thriller stars three Oscar winners — Al Pacino and Hilary Swank as cops and Robin Williams as the psycho they're chasing — and is directed by Christopher Nolan, 31, the innovator who made us all think backward in Memento, only adds to the film's hypnotic allure. It's taut, tense and terrific.

Pacino, in one of the high points of his remarkable career, plays Will Dormer, an LAPD whiz sent to the Alaskan town of Nightmute to investigate the murder of a teenage girl. From the opener, with Will and his partner, Hap (Martin Donovan), flying over a glacier, an atmosphere of unease is firmly established. The tension between the partners is palpable — evidence-tampering on past cases can bring down both their careers if Hap spills what he knows to Internal Affairs.

Will, whose last name, Dormer, evokes sleep, isn't getting any. And the Alaskan light is relentless. A sharp-eyed local cop, Ellie Burr, incisively played by Swank, tells Will this is the season of the midnight sun, when darkness just doesn't fall. Even when sleepless Will yanks the drapes shut in his hotel room, the light glares. In Hillary Seitz's script, loosely based on an austere 1997 Norwegian film of the same name, the sun is a metaphor for a conscience that won't sleep. Such windy attitudinizing could break the spirit of a movie and an audience.

Not here. Nolan matches his Memento achievement with another triumph of style and substance. Setting a trap for the killer on a misty beach, Will accidentally shoots Hap. Or is it an accident? Will registers the fear in Hap's eyes before he dies. So does the killer, who watches in hiding.

As Walter Finch, a novelist who befriended the murdered girl, Williams doesn't enter the film until near the midpoint, but he brings a scary intensity to the role that's electrifying. Trying to establish a bond with Will, first by phone, then in a meeting on a ferry, Walter talks with calm reason: "Killing changes you, Will. It's like awareness." Nolan stages a thrilling chase for cop and suspect across moving logs, but it's Walter's psychological pursuit of Will that makes this one of the year's best movies. As Will goes sleepless for six days, Pacino — looking more ravaged than he ever has onscreen — lets us see this alert, quick-witted cop slowly, wrenchingly come unglued. It's a brilliant performance in a film that will keep you up nights.

“I'm Yours”

Jason Mraz re-emerged after his disappointing second album with this lead single, a Jack Johnson-esque ditty about giving yourself fully to someone else. The success of the reggae-tinged song (it earned two Grammy nods and a spot on the Billboard singles chart for well over a year) was something the folk-pop singer never predicted when he wrote it in 15 minutes at home. "I played a happy-hippie chord progression that would probably work without 50 different Bob Marley songs," he told Rolling Stone. "I thought, 'It's too novelty. This is a nursery rhyme,'" concluding that "you can never guess what's gonna be a hit."