SAN FRANCISCO — He's the reason adults of a certain age can't stop themselves from finishing the song line beginning "M-I-C-K-E-Y," the force causing untold legions to see marching mops when they hear the rousing strains of "The Sorcerer's Apprentice."

But the story of Walt Disney the man sometimes gets forgotten in the telling of his legend. Descendants of the 20th-century innovator hope to fix that disconnect with The Walt Disney Family Museum, opening this fall in San Francisco.

"My dad's story is an inspirational story," Disney's daughter, Diane Disney Miller, said. "I want people to understand his character and how he pursued his career."

And have fun.

"Our museum will be entertaining," she said. "That's what dad was all about."

Since Disney's death at 65 in 1966, some of the coverage of the man behind the mouse hasn't been the happiest thing on Earth, starting with the oddly persistent falsehood that his body was cryogenically frozen. He was cremated and buried.

Meanwhile, the icon has become so distinct from the person that some younger people think "Walt Disney" is a made-up corporate character, said Richard Benefield, founding executive director of the new museum.

Even for those who know, the story can get confused.

"People remember very specific things about Walt and it's bits and pieces and you don't necessarily remember them in a collective way," Benefield said.

Seeing Disney's work in one place — the cutting-edge animation, the theme parks, the technological advancements — "the order of magnitude is pretty outstanding," he said.

Still under construction, with an opening date of Oct. 1, the museum will feature 10 galleries, starting with Disney's beginnings on a Missouri farm. Among the artifacts is the form on which a 16-year-old Disney lied about his age (changing his birth date from 1901 to 1900) to train as a Red Cross ambulance driver in World War I France; he arrived as the war ended. Exhibits include listening stations and more than 200 video monitors as well as interactive displays.

The museum consists of three historic buildings that have been redesigned and upgraded by Page & Turnbull of San Francisco, with interior architecture and installations by the Rockwell Group. It is set in the Presidio, a former Army base with sweeping views of the Golden Gate Bridge. That puts it, said Benefield, "in the center of the animation universe right now" with Lucasfilm Ltd. to the north and Pixar to the east.

Across the San Francisco Bay, Pixar co-founder John Lasseter is delighted about the new venture.