On 5 November 2009, a lone attacker strode into the deployment center at Fort Hood, Texas. Moments later, 13 Department of Defense (DoD) employees were dead and another 32 were wounded in the worst terrorist attack on U.S. soil since September 11th, 2001. This book is an examination of the counterterrorism lessons learned from the Fort Hood attack, which evidences the need for a more comprehensive and coordinated approach to counterradicalization and homegrown terrorism across all agencies which are critical to keeping our country safe.