This comprehensive report focuses on the global problem of nuclear proliferation networks and nuclear black markets. It provides a detailed case study of a damaging proliferation network centered in Pakistan – a partner in NATO, an ally in the struggle against al-Qaeda, and not a rogue state. Chapters written by experts describe Pakistan’s nuclear programs, nuclear black markets, engineer A. Q. Khan and the proliferation from Pakistan, the end of the Khan network, Pakistan’s nuclear oversight reforms, trafficking in radioactive materials, global efforts to stop illicit nuclear trade, and policy options.