On its surface, the documentary "My Architect," which traces an illegitimate son's painful quest to understand a distant father, is about dishonesty.

But the film's subtext is the more baffling link between creative genius and human fallibility, between a man who created some of the 20th century's most moving architectural works and one whose personal life left deep psychological scars on those closest to him.

The film follows director Nathaniel Kahn from Philadelphia to Bangladesh as he explores the life of his late father, Louis Kahn, one of America's most revered architects, who died in 1974. Such buildings as the 1953 Yale University Art Gallery, the 1965 Salk Institute for Biological Studies in La Jolla, Calif., the 1972 Kimbell Art Museum in Texas and the capital buildings at Dhaka in Bangladesh — not completed until 1983 — rank among his most lasting masterworks.

But beneath this public success, Kahn concealed a series of darker, private secrets. In addition to his wife, Esther Israeli, and daughter, Sue Ann, he kept two other families. The architect, an elfin man whose face was scarred in a childhood accident, had a daughter with an employee, Anne Tyng. The film's director is Kahn's son by another mistress, Harriet Pattison.

Destructive creative geniuses have always made for good stories. Caravaggio was a murderer and a thief; Picasso's misogyny was legendary. Frank Lloyd Wright ran off with a client's wife, who was then famously murdered by a servant at Wright's Wisconsin studio.

The value of "My Architect" is that it neither glosses over the architect's flaws nor exploits them. Instead, it treats its subject with a delicacy and pathos that at times can be painful to watch. The wounds caused by Kahn's deceptions have yet to heal; the beauty of his architectural creations is as apparent as ever. Despite the personal nature of the story, Nathaniel Kahn, 41, is able to keep his eye focused on both. The film's revelation is that Kahn's human flaws and creative achievements are intricately intertwined. Ultimately, it is the work that redeems the life.

A WALKING CONTRADICTION

Judged by conventional standards, Louis Kahn's life was in many ways a mess. Despite his reputation as one of the country's greatest architectural talents, most of the projects he designed were never built. He died roughly $500,000 in debt. His body was found on March 17, 1974, in a bathroom at New York's Pennsylvania Station and lay unclaimed in a city morgue for three days. The mostly fawning obituaries omit any mention of his secret families. Although his two mistresses and illegitimate children attended his funeral, few of those present had any idea who they were.

Yet over the course of a 40-plus-year career Kahn created at least half a dozen genuine architectural masterpieces. For a certain generation, his rugged monumental forms represented an important intellectual breakthrough. By bridging the seemingly vast distance between classical Modernism and a more primitive past, his work offered a way to liberate architecture from Modernism's increasingly dogmatic formulas. As the historian Vincent Scully once told me, "Kahn was the hinge on which Modernism turned."

Among the most influential of his works is the Kimbell Art Museum in Fort Worth, whose vaulted roofs, arranged in long parallel rows, remain one of the most exquisite designs of the 20th century. Made of bare concrete, the vaults are emblems of antiquity. Yet their power stems from deception. Each vault is cut in two along its ridge, allowing a soft light to wash down into the galleries.

The split vaults defy structural logic. We intuitively know that the slots should cause the vaults to collapse. Kahn solved this problem by inserting tension cables inside the concrete. But the cables are invisible to the eye, and the effect is magical, as if the concrete were able to defy gravity.

Such details define Kahn's genius — elevating him above almost every other American architect of his generation. They also hint at his obsessive-compulsive nature. Kahn was not a fluent talent. Architecture did not come easy to him; he could not churn out new ideas with the seeming ease of an architect like Le Corbusier. There is a methodical quality to Kahn's work. He spent months, for example, struggling with the Kimbell's roof design. Dozens of sketches, not shown in the film, still survive of the design process. Many could only be described as ugly, including an awkward mansard-like form and banal examples of more conventional roofs. Yet the sense of clarity Kahn eventually achieves is breathtaking. This single gesture seems to echo back through the arc of architectural history.

Other works are equally haunting. The stark plaza of the Salk Institute for Biological Studies, with its framing wood and concrete structures and slender reflecting pool extending out toward the Pacific Ocean, is one of the most photographed spaces in American architecture.

Deceit amid accomplishment

Perhaps his most important project is the National Assembly building at Dhaka, the capital of Bangladesh. Conceived as a series of interlocking concrete cylinders, the building's monumental halls are enveloped in a second skin pierced by a series of large geometric openings. The interstitial spaces, taut with energy, can be seen as an idealized version of the ancient medieval streets of the east — a vibrant social link between the outside world and the inner sanctuary. The entire composition is set within an enormous reflecting pool, as if to underline its spiritual purity.

The beauty of such works makes Kahn's detachment as a parent especially excruciating. Even as Kahn is struggling to imbue his work with lasting emotional meaning, his personal deceits are causing lasting emotional damage. Among the most chilling examples of Kahn's selfishness is a story about Tyng, who fled to Rome when she became pregnant with Kahn's child rather than cause a public scandal. When she returned, they broke up. Later, Nathaniel's mother, Pattison, was regularly asked to hide behind a locked door whenever Kahn's wife showed up at the office.

Watching Nathaniel Kahn unearth these stories about his father is apt to incite feelings of outrage. Yet Louis Kahn's life cannot be reduced to a simple narrative of good and evil. To his credit, the director has no interest in vilifying his father or placing him on a pedestal. Instead, he seems to intuitively understand that the path to forgiveness means entering the space where Louis Kahn felt most at home — the world of architecture.

Those closest to the architect — his collaborators and clients — understood this. It is the reason Kahn's mistresses are so quick to let him off the hook. Both Tyng and Pattison worked in Kahn's office. Tyng, a trained architect, collaborated on projects such as the unbuilt design for the Philadelphia City Hall. Pattison worked on the landscaping for the Kimbell. Both were unfairly neglected by history. But both seem to justify their relationships with Kahn in remembering the creative collaboration they shared with him.

It may be that Kahn's struggle to connect on a direct human level added to the emotional weight of his work. For whatever personal reasons — social pressures, a distrust of the world or a consciousness of its failings — he was able to convey his love for humanity most comfortably in the idealized space of architecture. Architecture is the place where he found shelter.

One of the most moving moments in the film involves the Indian architect Shamsul Wares, who is seen standing in the National Assembly building at Dhaka. Wares is trying to convey the importance that the building's creation played in a budding democratic state, a country that also ranked among the poorest in the world.

"He cared in a very different manner," Wares says, his eyes welling with tears. "He has given the people [something] that is important. You have to understand that to love everybody he sometimes did not see the very closest ones. That is inevitable for a man of his stature."

This spiritual quality is what has always drawn people to Kahn's work. Architects such as Renzo Piano and Tadao Ando, both now in their early 60s, are deeply affected by Kahn's ideas. But the split that defined Kahn's life may also be part of the reason his work has faded into the background in recent years. For a younger generation, the aesthetic purity Kahn was striving for represented a failed experiment. It embodied a world in perfect harmonic order, one that inevitably demanded a high degree of conformity.

The result was often a lie. Few could fully sustain that image. Since Kahn's death, the breakdown of the American family has become a central theme of contemporary culture. One of architecture's main missions has been to create an aesthetic language that reflects the psychological complexities once hidden underneath the veil of idealism.

That truth is best summed up in an image described at the beginning of the film. Louis Kahn calls Nathaniel's mother as he is leaving the office. She frantically prepares a dinner. Moments later, she is standing at the door to hand him a fresh martini in a frozen glass. By the end of the night, Kahn is sneaking back into his wife's home while a boy watches from the back seat of a car.

The child in that back seat is, of course, Nathaniel Kahn. But the world expressed in that moment sparked a revolution in architecture that continues today. The notion that architecture could embody an ideal of Utopian purity is not likely to be revived any time soon. It has been left to another generation to sort out the pieces.


Nicolai Ouroussoff is The Times' architecture critic.