Authors McCauley and Moskalenko argue that lone-actor terrorists may share common characteristics that could help identify high-risk individuals. Specifically, they examine the profile types: disconnected-disordered, in which individuals are loners with a history of mental disorder; and caring-compelled individuals who feel personal responsibility to bring to justice those responsible for making innocent others suffer. This article is part of a larger white paper covering various perspectives of terrorism and approaches to understanding the phenomenon.