The man standing in the doorway of the lab smiled confidently at no one in particular. After a decade living in Europe, he had learned that a simple smile was disarming. He was Pakistani, 36 years old, just over six feet tall, with a broad forehead, fleshy face, and thick, close-cropped black hair. He wore a Western-style suit but tucked his tie behind his belt in a way that made the ensemble seem like a costume. He spoke adequate Dutch and very good German, both accented by the lilt of his native tongue. Arriving at the Physical Dynamic Research Laboratory, also known as FDO, in Amsterdam on May 1, 1972, to begin his new job as a metallurgist, he had been escorted immediately to this office in the mechanical-science department, where he was to spend the next three years.

Frits Veerman, the laboratory’s young photographer, was surprised. He had been told his new officemate would be an impressive foreigner with a doctorate and a long list of academic publications. But Veerman had not expected the broad grin and the gleaming white teeth, not to mention the dark skin. The photographer stood, walked over, and stuck out his hand.

“Frits Veerman,” he said in Dutch, “welcome to FDO.”

“I am Abdul Qadeer Khan,” the man replied. “It is a pleasure to meet you.”

Many of the people who worked in the lab had advanced degrees, and in the hierarchical structure of the place—and of Dutch society in general—they tended to discount people like Veerman, who had only a technical degree and whose work as a photographer was deemed far less important than their own. Veerman had braced himself for the usual cold shoulder, but Khan seemed different. Veerman found him friendly and humble, interested in all the workers and what they were doing inside the complex.

After that first friendly encounter, the two men settled in comfortably opposite each other at a large desk. Whenever Veerman ventured out to photograph minute design changes in some piece of sensitive technology, Khan tagged along, asking questions. Khan began praising Veerman’s photographs—the prints were like works of art, he told him, with each detail clearly visible—and asked if he might have copies. The Dutchman thought this a bit odd, but he was flattered and complied happily. Khan eventually wanted to take his own photographs, and Veerman helped him buy a secondhand, high-quality camera. It all seemed to fit in with Khan’s insatiable curiosity.

From such beginnings, more than 35 years ago, A.Q. Khan emerged as the father of the so-called Islamic bomb and mastermind of Pakistan’s nuclear-weapons program. He established a private network for smuggling bomb-building technology and equipment to Pakistan, and then he reversed the flow and sold the same lethal secrets to Iran, North Korea, Libya, and, international investigators suspect, at least one still-unknown customer. For decades, the Central Intelligence Agency and European authorities watched as Khan stole the world’s most dangerous secrets and parlayed them into a global nuclear-weapons bazaar. Khan’s story remains in the news as the United States and other Western nations confront a defiant Iran over its nuclear ambitions, which have been nurtured by sophisticated technology courtesy of A.Q. Khan. In fact, should a rogue nation or terrorist group ever launch a nuclear attack, it is likely that the trail of destruction will lead back to Khan and his start at the lab in Amsterdam.