This book looks at the increasing militant activity in western Pakistan which poses three key national security threats: an increased potential for major attacks against the United States itself, a growing threat to Pakistani stability and a hindrance of U.S. efforts to stabilise Afghanistan. A U.S.-Pakistan relationship marked by periods of both co-operation and discord was transformed by the September 2001 terrorist attacks on the United States and the ensuing enlistment of Pakistan as a key ally in U.S.-led counterterrorism efforts. Top U.S. officials have praised Pakistan for its ongoing co-operation, although long-held doubts exist about Islamabad's commitment to some core U.S. interests. Thus this book also examines the influence of Islamist militants and the "talibanisation" of western Pakistan, which appears to be ongoing and may now threaten the territorial integrity of the Pakistani state. This is an edited, excerpted and augmented edition of various government publications.