In the second edition of his book originally published in 2013, Simon (The Terrorist Trap: America's Experience with Terrorism, 1994, etc.) focuses his scholarship on spree killers who act alone or with minimal assistance.
Whether Timothy McVeigh, Theodore Kaczynski, Nidal Malik Hasan, Anders Breivik, Tamerlan Tsarnaev, Syed Farook, Tashfeen Malik, and other "lone wolves" should be labeled terrorists or something else—such as deranged mass murderers—matters to those who care about inflammatory language or reactions to it. In an appendix titled "Defining Lone Wolf Terrorism," Simon usefully discusses shades of gray in his word choices. The discussion is almost certain to cause disagreement among those who read it carefully, as the author’s case for his use of the word terrorism isn't altogether convincing. That phrasing conundrum aside, Simon has conducted extensive research in an attempt to categorize lone-wolf mass murderers and perhaps understand some of their actual motivations, going beyond what they might proclaim publicly. The author’s five-part categorization encompasses secular lone wolves, religiously motivated lone wolves, single-issue lone wolves, lone wolves motivated by financial gain, and severely psychologically disturbed lone wolves (often paranoid schizophrenics). Simon is especially intriguing in his discussions of why men dominate the lone-wolf category and why women rarely act in such a manner. Aside from his explorations into gender differences, the author breaks little-understood ground by exploring how easy access to the internet has influenced the formation of the terrorist mind and allowed killers to achieve notoriety after their sprees. Simon's historical perspective also offers context regarding past examples of lone-wolf killings in the U.S.
Some of Simon's research validates common-sense conclusions about extreme human behavior, but the book contains enough fresh findings to recommend it to those who want to delve into such dark corners.