On February 5, 2003, Secretary of State Colin Powell issued a dire warning to the United Nations Security Council in an effort to convince the international community that Iraq possessed weapons of mass destruction in violation of Security Council resolutions. He stated: “There can be no doubt that Saddam Hussein has biological weapons and the capability to rapidly produce more, many more. And he has the ability to dispense these lethal poisons and diseases in ways that can cause massive death and destruction.”As we know now, these conclusions were not based on solid intelligence. In fact, after the March 2003 U.S.-led invasion of Iraq, investigation of Iraq’s WMD programs has shown that every single U.S. allegation regarding Iraqi biological weapon activities was wrong. How did the United States get so much so wrong about Iraq’s biological warfare program?Although the severity of this intelligence failure was a shock, intelligence agencies have a long track record of either underestimating or overestimating their adversaries’ BW capabilities and intentions. The United States also encountered serious problems assessing the Iraqi BW program before the 1991 Gulf War and the Soviet BW program throughout the cold war—although our intelligence on these programs was better than commonly understood.States developing biological weapons have strong incentives to keep their plans and capabilities secret due to legal, normative and strategic reasons. As a result, these states engage in extensive deception-and-denial operations to conceal the existence and capabilities of offensive programs. Properly assessing the information that is collected is complicated by the multiuse nature of biotechnology; the overlap between offensive, defensive, and civilian activities; and the lack of easily detectable signatures for offensive programs. As a result, biological weapons are a notoriously difficult target for intelligence agencies.Good intelligence is the first line of defense against biological weapons. Conversely, poor intelligence complicates efforts to develop and deploy defenses, engage in diplomacy, conduct inspections, and undertake military operations. Chapter 4 of the book describes the challenges in collecting and analyzing intelligence on biological weapons, examines the reasons for successes and failures in the Iraq and Soviet cases, and provides recommendations on how to prevent such intelligence failures in the future.In his announcement in 1969 that the United States was terminating its offensive biological weapons program, President Richard Nixon stated, “Mankind already carries in its own hands too many of the seeds of its own destruction.” Over the past sixty years, the world has avoided the worst consequences of biological warfare. World War II ended before the United States perfected its ability to mass-produce bombs filled with anthrax spores for use against Japan. The revolution in biology and biotechnology blossomed in the United States free of any military interest or influence because the country had already abandoned its offensive program. The Soviet Union, which aggressively sought to apply advances in biotechnology to biological warfare, collapsed before it was able to significantly achieve this objective. Will the world be so lucky at the next turning point? Maximizing the benefits that can be derived from advances in biotechnology and biomedical research while minimizing the risk of these advances being misused for hostile purposes will be one of this century’s most enduring challenges.