Despite the rise in the number of attacks by lone-wolf terrorists, the lone-wolf threat has largely been neglected by academic researchers and counterterrorism practitioners. The nature of the lone-wolf terrorist has introduced new challenges to law enforcement and counter terrorism unlike the more discussed problems of international group terrorism. This book suggests, however, that policies created to help deter group terrorism could be useful in detecting and deterring lone-wolf terrorists. The existing policy framework for group terrorism deterrence may have great utility in the fight against lone wolves, but policy use and effectiveness requires a careful examination of the characteristics unique to lone-wolf terrorism to ensure that the deterrence policies match. This book uses the comparative method and examines three case studies of lone-wolf terrorism from the United States and Europe: the Fort Hood shooter of 2009 (Major Nidal Hasan), the Boston Marathon bombers, and Anders Behring Breivik of Norway. By examining the unique circumstances of each case, this book determines what policies were and were not effective and in need of adaption to deter the threat of lone-wolf terrorism.