Light, Nature, the scale of the human body-the modernists believed these elements could be used to cure many of the world's social ills. Few architects have clung to that faith more than I.M. Pei, the octogenarian who has translated that formula into myriad highly refined architectural landmarks.

At 86,Pei is approaching the twilight of a long and successful career that includes the redesign of Paris' Louvre, Boston's Hancock Tower, the East Wing of Washington's National Gallery- all icons in their repective cities. So it came as a surprise a year ago that Pei had decided to take on UCLA's $600-million new hospital, the largest component in a $1.3-billion medical complex that will replacethe existing facility, which was damaged during the 1994 Northridge earthquake. Hospitals are notoriously cursed commisions for architects; Complex organizational requirements and high cost of increasingly sophisticated technological hardware mean that architecture inevitably becomes a secondary concern.

Yet Pei's design, unveiled Jan. 19, shows us how even the most fundamental architectural tools-when skillfully manipulated-can do much to foster a humane environment even under extreme constraints. This is not one of Pei's greatest works, but given the project's constraints, the project is a masterful piece of light, nature, and scale-one where architecture can function as an integral tool in the healing of the human psyche. In that sense, it is a critical step toward a more enlightened understanding of health care.

The existing medical center faces Westwood Plaza, embedded in a maze of parking structures on the extension of Westwood Boulevard that forms the main entry to the school's medical campus. Completed in 1954, the original structure was organized as two elongated parallel buildings, one housing doctors and research, other patients, with offices tucked in between. But during a series of subsequent expansions the complex evolved into a labyrinth of interlocking buildings. The center is now a chaotic, 3.1 million-square-foot complex whose repetitive rooms are bound together by 27 miles of corridors where patients, doctors, and visitors scurry back and forth with rat-like determination. It is a structure that fosters anxiety, not calm.

The new design, by comparison, will be an oasis of rationality. Conceived as a cluster of smaller communities, the first three floors form a massive plinth that unify the design. In order to preserve the sense of order, however, there are three main entries: Most inpatients will enter through the east lobby from a landscaped rotunda at one end of Westwood Plaza, while pediatric patients will arrive from the west, along a second, tree-lined drive along Gayley Avenue. Trauma patients, meanwhile, enter through a more discreet entry along Charles E. Young Drive South or will be flown onto one of two helicopter pads, from where they wishoot down into the building via high-speed elevators.

The separation of patients and families into distinct, interdependent units, however, is strongest on the upper floors, where Pei breaks the building mass into four semi-detached volumes, creating a more comforting sense of scale. Arranged in clusters of 32 rooms, the wards connect on each floor through light-filled public rooms. Pei has staggered the towers so that windows won't look directly in on each other-a trick he used in his 1961 design for New York's University Village-allowing light to spill in from all sides and opening up views. Inside, each of the 525 rooms-all of them private-is equipped with an oversized window seat that can be converted into a bed, where visitors can curl up at night alongside the patients they are visiting. The idea is to create a hierarchy of increasingly intimate communities-an antidote to beaureaucratic anonymity.

Pei Lamented in a recent interview that the site's size does not allow for more public space, something he feels would have strengthened the building's design. Ideally, on a site twice as big, the entry level would have opened onto large internal gardens, lobbies would have soared. Equally important, the upper floors would have included more generous public rooms, large terraces where patients could escape the confinement of their rooms to mingle with one another or rest in the fresh air and light. And the architectural forms-with more room to breath-might have been closer to the strong geometrical compositions that have marked Pei's buildings in the past. Here, the forms are somewhat dull and static.

Nonetheless, Pei has found ways to infuse his design with nature and light. On the ground floor, a partially sheltered garden court flanks the hospital's east lobby, where visitors can temporarily escape the bustle of the hospital within, while to the south, an outdoor restaurant plaza connects the building to the existing Medical Plaza. The triangular form of the structure's southern glass facade-flanked by two stone-clad towers- steps back to create a series of outdoorterraces. Pei's desire-to create a more open, therapeutic environment-extends beyond the boundaries of the complex. Pei wants to connect the new structure to a larger urban context, to fuse this cloistered world within a city. In his scheme, an alley of eucalyptus trees will line Westwood Plaza to conceal the banal existing buildings and give the campus a strong central axis. A traffic circle will mark the hospital's main entry and help bind together the medical campus' various buildings. Reflecting pools will add an element of restfulness to the scheme, which seeks to turn what is now a bustling, chaotic urban street into a more calming, bucolic context. The idea is that architecture, too, can heal, that it can function as a framework for an enlightened community, one that can even uplift the soul.

During the 1920s, avant-garde architects such as Konstantin Melnikov proposed highly rational environments that were intended to heal their inhabitants both morally anhysically. Melnikov's Laboratory of Sleep-never built-was intended to lull workers into a magically rejuvenating dream world. In the Hollywood Hills, Richard Neustra's 1927 Lovell Health House with its open steel and glass frame was meant to have similar-if less fantastic-therapeutic qualities.

Such idealism has since been tempered by the well-recorded failures of postwar urbanism. Modernism's utopia bent has long been supplanted by architecture that seeks to reveal the inherent complexity of our social and cultural structures rather than to transform it. In that sense, Pei's architecture to accomplish so much it insists on architecture's humanist mission, on its ability to elevate the human condition.