It has been two decades since Nathaniel Kahn's acclaimed documentary, My Architect: A Son's Journey (2003), renewed interest in architect Louis I Kahn, the American designer of our National Parliament building, who is considered one of the most transformative examples of 20th century global architecture. I keep wondering what enabled My Architect to strike such a popular chord around the world and become a classic. Is it Kahn's monumental architecture, his mystical style of teaching, his complicated personal life, or something else? Conceived as a self-reflective journey – albeit through architecture – in search of a father long gone, the film was the brainchild of Nathaniel Kahn (hereafter Nathaniel), Kahn's son born out of wedlock. Nathaniel was 11 years old when his father died of a heart attack in 1974 in the men's room of New York's Pennsylvania Station, after a 24-hour flight from India and Bangladesh. Nathaniel met his father only a few times during his life.

The tragic set of events decidedly contributed to Kahn's legend. Through a probing, at times emotional, study of his celebrated father's buildings, Nathaniel seeks to understand the enigmatic father he rarely saw and barely knew. The result is a personal reflection on the mysterious intersection of private life, public identity, and their roles in the creation of architecture.

Along the journey, Nathaniel interviews renowned architects and planners who were either influenced or repelled by his father, the various people who met him, and, most of all, the two colleagues-turned-lovers – Anne Tyng and Harriet Pattison – each of whom bore a child with Kahn (while Kahn remained married to his wife, Esther Kahn). Nathaniel, Pattison's son, is one of them. The archaeology of personal secrets interwoven with an epic narrative of architecture, built and un­built, spread across the US, Jerusalem, Iran, India, and Bangladesh, unleashes a philosophical energy that compels the audience to ask questions concerning human nature, creativity, and the enigma of their inter-relationship. The film also examines the nature of the father-son relationship, further compounded when architecture plays the abstract role of surrogate father.

Nathaniel's journey resonates with classic filial quests – Homer's Telemachus looking for his father Odysseus, or Parsifal finding a father figure in a hermit uncle. The fatherless son's narrative is a timeless narrative, an archetype: losing his father at a tender age, and thereafter setting out to find him, the son initiates an existential journey of self-discovery. Telemachus' search for his father who would come back to restore his mother Penelope's honour, for instance, takes on redemptive meanings deeper than merely yearning for a lost father.

"As a little boy, I never quite believed that Lou was gone," Nathaniel reminisces, "I would always look for him in crowds. I'd see a white-haired man turning the corner and think maybe it was him." Nathaniel's Telemachian desire is neither to rescue his mother Pattison (a landscape architect who collaborated with Kahn in the design of the Kimbell Art Museum in Texas) from surrendering to banal fatalism nor to simply reconstruct a father from stratified memories. Nathaniel starts off the documentary with the burden of his own scandalous origin, yet in his search he remains resolutely philosophical about the nature of conflicts between his father's personal life and creative endeavours.

The audience is left wondering to what extent does one privilege personal narratives in the rather amorphous process of aesthetic appreciation. Nathaniel's pilgrimage inadvertently criticises formalistic architectural pedagogy that isolates the analysis of architectural forms from the personal sagas of form-givers. By imagining the father in the realm of architecture, My Architect reaffirms, if subconsciously, the educational importance of aesthetic criticism that, among other things, includes what could be called the interior stories, anxieties, and desires of the designer.

The amazing footage of Kahn – walking around absentmindedly, talking to students like a yogi, and drawing with charcoal – shed new light on the ways in which architectural historians discern the kind of impulses and tensions that sustain the sublimity of Kahn's architecture. My Architect's dramatic finale – expressed through the exquisitely filmed parliament building of Bangladesh – exudes a son's reflective delight in at last being able to reconcile with his dead father. Nathaniel chooses to see the building through the bedazzled eyes of a solitary, prepubescent Bengali boy, a reference to Nathaniel's own age when his father died. This is the frozen moment that serves as the film's official image.

Inside the parliament building, Nathaniel interviews architect Shamsul Wares, who delivers a startling, if not the ultimate, message: that personal failings should not blind us to the genius of a great artist and that a son must seek his father not always in the father's fulfilment of familial duties, but sometimes in the humanity of his aesthetics.

Father-seeking was an integral theme of modernist architectural history. If the archetypal fatherless son's search bears redemptive spirit or the hope of performing spectacular things – to form a utopian society, to remind humanity of a golden bygone era, or to return civilisation to a pristine condition – early historians of modern architecture articulated the image of the architect with similar filial devotion. In their formulation, the architect became a "fatherly" figure, a saviour, a master, under whose tutelage the phoenix of modern utopia would rise from the ashes of dysfunctional cities. The historian often played the role of the fatherless son, imagining the advent of a visionary father: upon reconciliation they would resituate the state of architecture in the Garden of Eden to begin civilisation anew.

Despite the film's inherent melancholy, people discover My Architect as a populist case study, so to speak, to inquire into the historical and sometimes fateful alliance between the modern architect and the historian, an alliance that often transpired within the mould of the archetypal filial quest.

The legend of Louis Kahn remains strong. I wonder if it is the enigma and magic appeal of a father figure that inspire people to feel the way they do toward Kahn.

Dr Adnan Zillur Morshed is an architect, architectural historian, urbanist, and professor. He teaches at the Catholic University of America in Washington, DC, and serves as executive director of the Centre for Inclusive Architecture and Urbanism at Brac University. His most recent book is Dhaka Delirium.