From the Introduction: 

Over the past three decades, official investigations in the United States and Europe came close on several occasions to pulling the lid off of Pakistan’s nuclear smuggling network. But to protect strategic relationships with Islamabad, those inquiries were scuttled by intervention at the highest levels of government. The opportunities to roll up the network were lost and the spread of nuclear technology continued.

Suggestions by President George W. Bush and members of his administration that the Khan case is a success story would be laughable if the implications were not so dire. Many of the Khan network’s operatives remain free and live openly in Europe, Asia, and even the United States. The underground trade in nuclear technology continues, and the opportunities for terrorists to get their hands on atomic weaponry are expanding. Many in Pakistan’s military, intelligence, and scientific communities are closely allied with the Taliban and al Qaeda, groups that US policy in the years before 9/11 helped foster. The lure of profits, combined with ideological, religious, and ethnic loyalties creates conditions for potentially deadly cooperation between those with access to nuclear technology and our bitterest enemies.