In the late 1960's and early 1970's, the majority of American and international terrorist groups were composed of males and females who were flexible, college-educated, well-trained, urban, multilingual, well-traveled, and reasonable sophisticated middle-class young people. They could adjust to change and still complete a mission, even with last-minute alterations. Examples cited are the Japanese Red Army, the Weather Underground, and the Symbionese Liberation Army (SLA). The group profile that emerges reflects organizations which blended highly motivated and well-educated members with a criminal element. A profile of today's terrorist, especially Middle Eastern, indicates members who are poorly educated, from very large families unskilled and unemployable, illiterate, rural, undisciplined, and ill-trained male refugees. They are young, members of street gangs, know little of politics, and hate Americans. There is an absence of the specific criminal type and the much lower educational level of followers in today's terrorist groups. Few are willing to engage in suicidal missions away from their homelands. Today's terrorists are individuals and organizations who succeed only when the system fails. A general profile of the membership of radical right-wing groups, such as the Ku Klux Klan and the neo-Nazis, reflects people with limited education, members of the racial and religious majority, and people who have experienced social or economic failure. The violent activity of the right has been in the form of attacks on police officers, the robbery of banks and armored cars, and similar criminal acts. 3 tables and 21 footnotes.