"Visionary San Francisco" is the largest effort to date of the museum's seven year-old department of architecture, which is under the direction of Paolo Polledri. Mr. Polledri's thesis is that San Francisco, a city that once moved ahead with a self-assurance equal to that of ancient Rome, has now deteriorated into a provincial factionalism, its every move stymied by conflicting interests. The city desperately lacks a sense of a "shared vision," he states in his introduction to the catalogue accompanying the exhibition, and he makes clear that his motivation in mounting the show is to attempt to stimulate the city's public spirit once again.