Terrorism: The Essential Reference Guide. Edited by Colin P. Clarke. Santa Barbara, CA: ABC-CLIO, 2018. 346 pages. Acid-free $94 (ISBN 978-1-4408-5628-0). E-book available (978-1-4408-5629-7), call for pricing.

If you’ve been so numbed by the terror attacks of recent decades that you can’t keep track of them, Dr. Clarke (Rand Corporation) is here to help you. He summarizes the long and controversial history of even defining terrorism—much less dealing with it—in a series of introductory essays, but the bulk of this volume is an encyclopedia of modern terrorism.

From the unforgettable 9/11 attacks to the long-gone Baader-Meinhof Gang, there are more than one hundred entries about the actors and organizations that have used murderous violence to force the global community to pay attention to them. The entries reflect a broad understanding of terrorism; many entries involve groups that wage long, ideological terror campaigns around the world, but others address purely domestic American lone wolf terrorists such as Dylann Roof and Ted Kaczynski.

Because this is a reference guide, it can be easy to miss the connections between the topics, but Clarke helps readers in three ways. Each entry ends with “See also” pointers to related entries in the book, and there is a chronology of modern terrorism. Best of all, the index is an impressive forty-six pages. That’s especially helpful because readers will have trouble finding some of the entries just by guessing how they are titled alphabetically; the big index gives them many ways to find what they are seeking.

Other helpful features include sixty-eight pages of primary documents and a bibliography. There are also a few black-and-white photographs within the entries and a list of contributors.

The same publisher recently released Spencer C. Tucker’s U.S. Conflicts in the 21st Century: Afghanistan War, Iraq War and the War on Terror (ABC-CLIO, 2016). It is organized much like Clarke’s guide but has many more entries on military topics, as well as numerous biographical entries.

Two related reference works are Extremist Groups: Information for Students (Thomson-Gale, 2006) and Patterns of Global Terrorism (Berkshire Publishing Group LLC, 2005), edited by Anna Sabasteanski. Obviously, both sets are dated for such a rapidly evolving topic, but they do provide substantial background on a much wider range of topics. For instance, the Thomson-Gale set includes organizations such as Earth First.

The Sabasteanski project is quite different from the others in that it consists mainly of US State Department reports and supplementary materials. Some reports are presented by geographic areas and some by chronology of events.

The Clarke work deserves consideration by any public library maintaining a collection of reference resources about current events, but it may not be needed by a library that already owns the Tucker volumes.—Evan Davis, Librarian, Allen County Public Library, Fort Wayne, Indiana