This volume was completed just before Pakistani President Musharraf imposed a state of emergency in November 2007. The political turmoil that followed raised concerns that Pakistan's nuclear assets might be vulnerable to diversion or misuse. This book, which consists of research that the Nonproliferation Policy Education Center (NPEC) commissioned and vetted in 2006 and 2007, details precisely what these worries might be. Dr. Ashley Tellis of the Carnegie Endowment for International Peace and Dr. Peter Lavoy, now the National Intelligence Officer for Southwest Asia at the National Intelligence Council, were instrumental in the selection of authors as well as producing original research. Thanks is also due to Ali Naqvi and Tamara Mitchell of NPEC's staff who helped organize the workshop at which the book's contents were discussed and who helped prepare the book manuscript. Finally, special thanks is due to Professor Douglas C. Lovelace, Jr., Ms. Marianne Cowling, and Ms. Rita Rummel...