Terrorism: Commentary on Security Documents is a series that provides primary source documents and expert commentary on various topics relating to the worldwide effort to combat terrorism, as well as efforts by the United States and other nations to protect their national security interests. Volume 138, The Resurgent Terrorist Threat, examines the changing threat of terrorism and why after over a decade of concerted effort terrorism is still a threat.

The documents included in this volume include reports on the future of terrorism, cyberterrorism, the Project BioShield Act, combating terrorism in Africa, and the resurgence of terrorist organizations in Syria and Iraq.