Whereas Renzo Piano's addition to the Los Angeles County Museum of Art was constrained by a need to adapt to somewhat inhospitable surroundings, the new California Academy of Sciences in San Francisco has what most architects would consider a dream site: Golden Gate Park. The Renzo Piano Building Workshop has done so many museum additions (the High Museum in Atlanta, the Morgan Library in New York, soon the Art Institute in Chicago, and the Isabella Stewart Gardiner Museum in Boston) that it has acquired a reputation as an architectural Mr. Fix-It. But its best museums—the de Menil Collection in Houston and the Nasher in Dallas—are stand-alones. So is the California Academy, which has the architect's well-known hallmarks: a light, elegant steel structure; precise details that celebrate technological competence; lots of glass; and a layout as simple as a diagram. This produces a calm, rational, sane place. Perhaps that's why Piano's buildings work best on their own—they are a world apart.