Henry Wilcots distinctly recalls his first encounter with Philadelphia architect Louis Kahn. It was 1963 and he was staying in a hotel in Dhaka, then in Pakistan and now the capital of Bangladesh. Someone tapped on his door, and when he opened it, Wilcots saw a rumpled, silver-haired man holding a flask. He wanted to know whether Wilcots had any gin. He needed it to brush his teeth.

Kahn, who was at the height of his fame, had been hired to create in Dhaka a new second capital for Pakistan. Wilcots was just starting out in architecture, designing military buildings for a small American contractor. He had come to this strange, faraway place because he and his wife wanted an “adventure” before having children. Wilcots also knew that as an African American, getting a job in the United States would not be easy. ... Few people know that Wilcots was responsible for completing Kahn’s biggest and most prestigious project.

“If it hadn’t been for Henry, goodness knows how the project would have been finished following Lou’s death,” marveled Nicholas Gianopulos, the structural engineer who helped Kahn with the parliament building — that is, until Kahn stopped paying his firm, Keast & Hood.

While Wilcots worked under the radar for decades, the Bangladesh complex that he completed is regarded by scholars as one of the greatest designs of the 20th century. It “possesses a monumentality unlike anything to come before it in the history of architecture,” enthused Robert McCarter, a professor at Washington University in St. Louis, in his book on Kahn’s work. In Bangladesh, which became independent of Pakistan in 1971, the complex remains a source of immense national pride and appears on the 1,000 rupee note. Its plaza, which gets a cameo in My Architect, functions as a kind of national town square.

Wilcots, now 89, is retired from architecture, but the Bangladesh government still relies on him to interpret Kahn’s intentions. Just recently, they sent a delegation to review the construction drawings at the University of Pennsylvania Architectural Archives and asked Wilcots to walk them through the details.

During a leisurely afternoon conversation at his Chestnut Hill apartment, Wilcots just shrugged when asked how he felt about the obligation that fell on his shoulders after Kahn’s death. He never intended to take a job with Kahn in the first place. “I had always intended to move back to Des Moines,” where he had grown up in a family of 14 children, he explained. “I’m basically a Midwesterner.”

Wilcots’ story is especially remarkable because black architects are almost invisible in the profession, making up less than 2 percent of the total nationally. Over the decades, Philadelphia has nurtured designers such as Julian AbeleWalter Livingston, and Emanuel Kelly, yet today you can count on one hand the number of black architects practicing in the city.