<P>This book examines ‘national security panics‘ that led to major U.S. foreign policy shifts. <P></P>A national security panic is a period when the public was gripped by a widespread fear of imminent threat from an enemy allegedly bent on the destruction of the United States, yet with hindsight, the public fears are known to be based on highly inaccurate portrayals of the actual military threat at the time. The book argues that scholars should try to understand these periods of public fear because they have had major policy consequences. The sources of these fears is much disputed, even though they are known, with hindsight, to have been based on highly inaccurate views of the actual threats at the time. The author examines four key cases: the ‘Red Juggernaut‘ panic (c. 1950), the ‘Missile Gap‘ panic (c. 1960), the ‘Window of Vulnerability‘ panic (c. 1980) and the ‘Iraq WMD‘ panic (c. 2003), and tests three groups of hypotheses about the sources of these widespread public fears: (1) Were these fears rooted in intelligence failures? (2) were these public fears largely caused by psychological biases among decision makers? (3) Or were these fears caused by intentional threat inflation by political actors? Unlike other works, this volume explores all these competing explanations within and across multiple cases, side-by-side. In the end, contrary to the explanations of many others, the author finds that the root sources of these public fears is primarily intentional threat inflation by political actors. It also demonstrates that in two of cases, the intentional threat inflation was led by challengers to the executive branch, indicating that even though executive branch power is vast, it is not the necessary condition many scholars contend that it is. <P></P><P></P><P>This book will be of much interest to students of US national security, US foreign policy, US politics, Cold War studies, and IR/Security Studies in general.</P>