Book excerpt: This book contextualizes the use of terror as part of wider movements of political contention, demonstrating that terroristic innovation occurs as part of wider historical processes rather than in a vacuum. Drawing on evolutionary theory, this study explains how terroristic groups innovate upon, transform, and abandon techniques of political violence in order to advance their causes against the state. The book further traces the processes through which the use of aircraft as weapons of destruction developed, from the first instances of aircraft hijacking in 1930s Peru, through Palestinian terrorism in the 1960s and 1970s, up to its adoption by al-Qaeda in the 1990s and leading to the 9/11 attack in 2001. This examination provides an essential focus on the techniques through which terror is achieved, offering a novel understanding of the mechanisms of political violence and the implications of counterterrorism on the evolution of terrorism