In light of the recent events in Pakistan, this excellent and chilling book has acquired added significance. It tells the unnerving story of how Pakistan acquired the bomb and distributed its secrets to North Korea, Libya, and Iran. At the center of the story is the redoubtable A. Q. Khan, who happened on nuclear secrets by chance while working for a European nuclear consortium in the 1970s -- and then controlled both Pakistan's national nuclear program and its external nuclear trading until he was forced to stand down in 2004. The convenient fiction, which was used to save the U.S.-Pakistani alliance, is that Khan was acting on his own when proliferating. This story was never credible and is torn apart in Levy and Scott-Clark's account. The authors demonstrate the lengths to which the U.S. government was prepared to go to play down Pakistan's nuclear machinations. This was particularly so at those points when it needed Pakistan most, while fighting the Soviets in Afghanistan in the 1980s and while fighting al Qaeda there more recently. When Washington did try to call a halt to the proliferation, however, as it did in the late 1990s, it did not get very far.