Terrorism became an issue of worldwide concern in the last third of the twentieth century. Terrorist tactics were not new; they had been used for centuries before being defined as terrorism. The word "terror" entered the political lexicon during the French Revolution's "reign of terror." In the late nineteenth century, at the beginning of the twentieth, and again in the 1920s and 1950s—all periods between major wars on the European continents—terrorism became a technique of revolutionary struggle. Stalin's regime in the 1930s and 1940s was called a reign of terror, but from the late 1940s to the 1960s the word was associated primarily with the armed struggles for independence waged in Palestine and Algeria, from which later generations of terrorists took their inspiration and instruction. After World War II, "terror" emerged as a component of nuclear strategy; the fear of mutual destruction that would deter nuclear...