Twenty years is a long time to walk a tightrope without falling off, and that's exactly what Tom Krens did. But news that the jet-setting, big-dreaming, free-spending director of the Solomon R. Guggenheim Foundation is stepping down has rattled the art world, and his departure will have worldwide repercussions.

Krens' departure throws one of the world's great art institutions--and its five satellites, all developed or expanded under him--into upheaval. It could stall the museum's momentum and up-ends its priorities: Will the Guggenheim's fierce campaign to stamp its global art brand on far-flung outposts around the world continue?

It also throws a spotlight on the booming Middle Eastern art scene, as Krens will stay on as senior adviser to oversee the building of the huge Guggenheim Abu Dhabi. The United Arab Emirates' cultural building project on Saadiyat Island has long been viewed as an entertaining mirage in the art world but, through his celebrity, Krens has overnight made Abu Dhabi a serious art destination.

Finally his departure raises questions about whether the movements and policies he endorsed will endure beyond his tenure. Krens canonized architects like Frank Gehry and Zaha Hadid as artists, exhibiting their models and drawings as art. He aggressively backed other nation's art stars, adding a curator of Asian Art at the Guggenheim and granting China's "gunpowder" artist Cai Guo-Qiang (he's used the material in his works) his first exhibition. And he was widely criticized for establishing a hand-in-glove relationship with such corporations as BMW and Armani--in 2000, the museum opened a retrospective of the designs of Giorgio Armani, who had become a major benefactor.

Krens stepped down, insiders say, because the museum was facing difficulties recruiting a director of the New York Guggenheim, given Krens' continued high profile at the parent foundation. (Last fall, the museum's director, Lisa Dennison, left for Sotheby's.)

But is he really going anywhere? Krens decision to stay on as a senior advisor, and overseer of the Abu Dhabi outpost, the Guggenheim's biggest and most front-burner project, is far from a disappearance. If anything, Krens can reinvent himself if he manages to pull of a "Bilbao effect"--reinventing a city through cultural tourism--in the United Arab Emirates. Don't wave goodbye just yet.

by Alexandra Peers

Photograph by Fred R. Conrad/The New York Times