This has been a remarkable, amazing year for the Seattle Art Museum, which opened the Olympic Sculpture Park in January and its new downtown museum in May. Attendance has been strikingly up, especially at the free-admission Sculpture Park, which has counted 400,000 visitors since opening and is a huge hit with the public. Perhaps a bit overshadowed, downtown SAM says it counted 177,000 visitors from May to September, which doubles the 87,000 for the comparable period in 2005, the last year of the old building.

Last week's opening of two special exhibits at SAM's downtown museum was in a way the real beginning of the new era for SAM. The hoopla of the unveilings is now past, with the largely very positive press reviews safely banked. Now the work begins. That would be putting on interesting shows now that there's really space to do it (the rooms for special and touring shows went up by 5,500 square feet to 14,000), and to do it right.

So here was still-beaming SAM director Mimi Gates introducing dignitaries from Kobe, Japan, where one show comes from ("Japan Envisions the West"). Mayor Greg Nickels was talking about sister city bonds with Kobe and struggling with the language barrier and practicing his bows with his mayoral counterpart. Many, many people took bows.

And then Gates happily turned over the program to SAM's curator for the show, Yukiko Shirahara, who led a group through the galleries. The show is a fascinating if rather scholarly exhibition about how Japanese artists first encountered and then adapted Western artistic forms. Not only that, SAM was opening another show, tracing 30 years of paintings by the marvelous Palouse artist, Gaylen Hansen, now in his 80s and going stronger than ever. The Hansen show particularly is not to be missed.

Everything seemed wonderfully right about the occasion. The shows were not blockbusters but something better than that for their originality, depth, and appropriateness to the region. Gates put her curators to the fore, as she is very good at doing. Indeed, the new SAM is very much an expression of the museum's curatorial teamwork and its extraordinary skills in displaying artwork, coming from years of continuity in its key staff members.

Instead of a feeling of letdown after the big opening show, displaying the marvelous new art SAM has acquired from local collectors, who now have a genuine showplace for their donated art, here was a sense of showing what this striking new museum can really do, year after year. It is a quantum leap, unmatched by any other cultural institution in the Northwest.

"This was our dream," Gates told me in an interview during the summer, speaking of the whole staff and the donors. "Now we have it! There's no sense of letdown, for the greatest challenge lies ahead. It is simply this: to show we can be a major art museum." If there is a more turned-on arts organization in Seattle than SAM, I can't think of it.

About 25 years ago, few would have said or predicted things like this about SAM. Seattle is a young city, so its wealthy collectors got a late start in raiding European galleries, long after prices had become prohibitive. The collections' strengths were in Asian art (thanks to founder Dr. Richard Fuller), Northwest native art (thanks to local collectors like the Haubergs), and African art (through a fluke when a major collector happened to come to Seattle for medical treatment and die here). There were (and are) huge gaps in the collection. The downtown SAM, designed by Robert Venturi, didn't really work well. The design soaked up too much space with staircases, and the architect's subtle ironies and allusions from the post-modernist style were lost on most people and soon faded into a tribute to a passing fashion in architectural taste.

"SAM was a traditional place, for people who love art," recalls Gates of the museum's fairly limited sense of itself. She arrived here in 1994 from the Yale Art Gallery and at first seemed to be a somewhat academic leader of SAM, being an Asian art scholar herself and coming from a university tradition. Instead, she was to install a dramatic new vision for SAM.

Gates is warm and friendly and unpretentious, and most of all a team-builder who deflects credit. But she has been absolutely central to the transformation of SAM to where it now has a real shot at being a major art museum. In our interview, I pried some of the story out of her.

She began to change, she says, at Yale, where that university and gallery, always feeling dangerously isolated from the troubled city of New Haven, Conn., began looking at how it could be "a window on the community." One show in particular, an exhibit of African art, filled the gallery with kids of many races, creating a buzz in the gallery and a passion in the director, then known as Mimi Gardner. When she got to Seattle, later to marry Bill Gates Sr., she came to think that turning a museum outward was a "natural direction" for such a tolerant and open-minded city.

Museums can be easily captured by their wealthy collectors and donors, who are not naturally inclined to bring in the masses. The first downtown SAM, for instance, had a small space for touring shows, as some of the trustees disliked blockbusters for the way they bring in visitors more interested in buying Monet tote bags than becoming members and really learning about art. In their view, a quite defensible traditional outlook, museums should not be jammed with dating couples and visiting conventioneers but rather should be "contemplative" spaces for communing with complex works of art, and open to all who want such an experience.

Rather amazingly, Gates changed SAM's sense of itself, really revolutionizing the place. She opened the advisory committee and the board to more diverse members, such as Asunta Ng, a leader in the Chinese community. She used a $1.2 million Wallace Fund grant to study all the ways SAM could be more responsive to the city around it, "broadening, deepening, and diversifying its audience." She changed a traditional mission statement about collecting, conserving, and displaying great art to a much simpler one that said it all in five words: "SAM: where art meets life." It might also be put this way: Where SAM met Mimi.

An unexpected reinforcement arrived in 1997. That was when several collectors, notably Bagley and Virginia Wright, long mainstays of SAM, and Jon and Mary Shirley, he of a Microsoft fortune, made clear that they would donate significant works of outdoor sculpture if SAM could find a good place for a sculpture park. At first, the site was going to be the envisioned Commons in the South Lake Union neighborhood, but that idea, for a big park, was twice rejected by voters. Next, the Trust for Public Land, with a new mission of developing urban open space, offered to try to find land, eventually spotting the SoCal oil storage site along Elliott Avenue, sloping down to Elliott Bay.

Touring the unlikely site, then a brownfield, Jon Shirley immediately declared it was the place, and later the Shirleys pledged $20 million in endowment so that Olympic Sculpture Park could be free admission and all the maintenance and security costs would be paid out of the endowment earnings, not burdening the budget of SAM. That was the catalyzing moment, changing everything.