When I first began writing on bioterrorism in the late 1980s [1], there were two main criticisms leveled at anybody who was dealing with this subject. The first was that you might be giving new ideas to terrorists, who were busy at the time setting off car bombs, hijacking planes, kidnapping individuals, and doing other types of conventional terrorist attacks throughout the world. The assumption then was that terrorists did not know much about biological weapons, so the less said or written about the subject, the better. The days of bioterrorism being a taboo topic, however, are long gone. Today, there are countless numbers of books, articles, Internet websites, television commentaries, and government reports devoted to this threat. The second criticism was that terrorists did not have the motivations or capabilities to effectively acquire and use biological weapons, and therefore any publications that warned about the threat would needlessly alarm the public. That criticism can still be heard today. However, since the consequences of a major terrorist attack with a biological weapon could be catastrophic in terms of lives lost and the medical, political, and social crisis it would produce, it is important to answer the skeptics so there can be little doubt of the need to prepare for the day when terrorists might unleash these weapons upon a civilian population.