Animation has always been a tip-of-the-iceberg art in which seconds of finished work represent weeks of thought and labor. Ever since he put Toy Story into production, John Lasseter, the reigning genius at Pixar and the new chief of Disney animation, has infused that arduous process with joy and a love for movie heritage - even as he’s taken cartooning (in the words of Toy Story’s Buzz Lightyear) "to infinity and beyond."

For anyone who’s followed Pixar closely, everything Lasseter has been saying in the wake of Pixar’s sale to Disney - about the culture of Pixar being more important than its economics - rings as true as a church bell. I interviewed Lasseter in 1995 when Pixar went through its first great growth spurt. "The essence of Pixar," he told me then, "is the technical and the artistic working together."

He might have added fun - but, of course, he didn’t have to, because that was evident everywhere. Personnel zoomed down hallways on scooters and filled their rooms or work stations with art books and toys and audio-visual platters of all types.

One of Lasseter’s prized possessions is his autographed poster of the international Japanese cartoon hit, My Neighbor Totoro, by his acknowledged master, legendary 2-D animator Hayao Miyazaki. Lasseter and his collaborators have helped prepare and promote exquisite English-language versions of Miyazaki’s masterpieces, including Spirited Away and Howl’s Moving Castle.

So when Lasseter says he treasures traditional animation and will bring it back to Disney, he’s probably not bluffing. When he was seeking collaborators for his first computer-animated feature, Lasseter said he "looked at guys who worked with clay, cel, sand, and pencils; no matter what the medium, I wanted to see if they were able to take a character and make us feel that it was breathing and thinking."

Lasseter shared the plot credit for Toy Story with Pete Docter, Andrew Stanton and all-around story whiz Joe Ranft (who died in a car accident last summer). All revered the great slapstick comedians: Ranft was a Laurel and Hardy man; Stanton said, simply, "Buster Keaton is God." Stanton co-directed A Bug’s Life (1998) with Lasseter and then directed Finding Nemo (2003); Docter directed Monsters, Inc. (2001).

Lasseter also has a gift for collaborating with artists and writers outside Pixar’s fold. Joss Whedon helped shape the final script of Toy Story before he became the king of cult TV with Buffy the Vampire Slayer, Angel and Firefly. Whedon shared an easy rapport with the animators - "We were raised on the same cartoons and toys," he said. And he enjoyed an active give-and-take with Lasseter: "I was having trouble with Tom Hanks’ voice [as the cowboy doll, Woody], and John suggested I watch a scene near the beginning of Nothing in Common, where he jokes with everybody as he walks through his office." That did the trick.

Recently, Lasseter has done what few mini-moguls have ever dared: take a maverick artist in and let him rip. Pixar’s 2004 smash, The Incredibles, was the work of Brad Bird, a man known to animators and production artists as a visionary and to executives as a troublemaker and a box-office question mark. A decade before live-action dysfunctional-family fables became the mainstay of the Sundance Film Festival, Bird wrote and directed a droll abused-canine saga called Family Dog for the 1987 season of Steven Spielberg’s anthology series, Amazing Stories. Bird immediately became as respected for what he wouldn’t do as for what he did. He refused to be part of the team that spun Family Dog into a series, because he recognized that a rushed episodic-TV schedule would rob his creation of the source of all its humor.

Bird’s 1999 feature, The Iron Giant, was a marvelous modern fairy tale about a huge robot from outer space who washes up on the shores of "Rockwell, Maine" in 1957. Bird took a haunting, wispy fable that the poet Ted Hughes wrote for his children after the suicide of their mother, Sylvia Plath, and turned it into a piquant variation on the ultimate fish-out-of-water tale, E.T. It was a box-office disappointment - and an artistic high-water mark.

Lasseter’s extraordinary love for all the details of moviemaking makes him special both as a director and a company leader. During Toy Story’s final stages I got to watch "cartoon dailies" with Lasseter, his animators and his techies. At one point, Buzz Lightyear came on screen, coiffing a troll doll. In his own stiff way, Buzz oozed confidence and finesse. The troll’s eyes blinked and the room erupted in wisecracks as the animators envisioned Buzz taking the place of Warren Beatty in Shampoo ("You are so much more beautiful than the other trolls"). Lasseter, though, concentrated on whether they could make Buzz’s combing stroke more vertical and modulate the troll’s blinking eyes right before he combed downward. Then the director sighed in admiration. "Buzz is good at everything ..."