The Scourge of Terrorism from the Middle Ages to the Twenty-First Century

Who, What, When, Where, Why?

by Marian Leighton


View First 25 Pages: (free download)


This is the first book covering the entire timeline as well as the actors and factors driving international terrorism in each phase of its development. It provides an historical journey across the terrorist landscape and offers insights and analyses of the successive challenges that terrorists have posed.

The narrative shifts from the Assassins of medieval times to the nihilists of Tsarist Russia to the left-wing, Marxist-oriented terrorist organizations of the Cold War era to the more recent Islamist-based groups, including their respective supporters and enablers: the Palestinians, Russia and the Soviet bloc, and Iran.

More than 20 years have elapsed since the terrorist attacks on the World Trade Center and the Pentagon. A new generation has grown up with little or no knowledge of these horrific events and the warning signs that preceded them. Moreover, the Covid-19 pandemic, unprecedented political polarization, the growing focus on climate change and social justice and, most recently, the war in Ukraine have relegated the threat of terrorism to the back burner of U.S. national priorities. But Americans must remain vigilant for danger signs that could portend a new terrorist strike.

A valuable resource for both specialists and general readers, The Scourge of Terrorism also posits that counterterrorism in the post-9/11 and post-Afghanistan era requires new strategies to supplant the primarily military approach of the past.


The Scourge of Terrorism is a timely reminder that politically and religiously motivated acts of violence have deep roots in history and will remain a permanent factor in international affairs. While motives and targets shift over time, innocents who suffer are always the victims. The author makes a valuable contribution by discussing new strategies for understanding and countering terrorist threats in the future. The book is highly recommended for laymen and experts alike.
--Benjamin Fischer, former Chief Historian of the CIA

Marian Leighton’s new book on terrorism is a must read for the counter-terrorism community. Her book will help this community better understand root causes of terrorism and identify warning signs of political violence. Her book is also a persuasive counterpoint for those ill-advised foreign policymakers who keep telling us all to pivot away from global terrorism and focus instead on China and Russia.
--Dr. Leif Rosenberger was a former counterterrorism official at the US Defense Intelligence Agency (DIA) and is currently a governance advisor in the Peacekeeping and Stability Operations Institute (PKSOI) at the US Army War College.

Throughout human history, groups of individuals have been subjected to violence from competing forces, whether in war or in more limited, even controlled, assaults, currently termed terrorism. Marian Leighton, with decades of experience as an intelligence community analyst, follows the development of terrorism from its roots as a localized attempt to harass a neighboring tribe or community to its current version as an international force capable of utilizing improvements in weaponry that enhance the effect such ventures have on their victims. While flying airliners into civilian buildings can be more dramatic and take many more lives than would butchering a local tribe, the immediate result of the attack may not always be more effective in striking at the emotional heart of the target group. In examining the progression of terrorism through the ages, Dr. Leighton offers a closer examination of its impact and potential in this more mobile and technologically sophisticated era.
--Richard R. Valcourt, Editor-in-Chief Emeritus, International Journal of Intelligence and CounterIntelligence

A remarkably comprehensive study, packed with new information and brimming with the wise insights of an intelligence practitioner. Every national security official should read it.
--Toby Harnden, author of First Casualty: The Untold Story of the CIA Mission to Avenge 9/11

About the Author

Dr. Leighton, a retired intelligence officer and terrorism specialist, is uniquely qualified to address the problem of terrorism going forward. She has a PhD in international relations from Columbia University and has focused on terrorist and counterterrorist issues both in the intelligence community and the private sector during her long career. Dr. Leighton’s most recent publication is Two American Crusades: Actors and Factors in the Cold War and the War on Terrorism, published in 2020.