Biological agents are defined as "disease-causing organisms and materials -- whether viral, bacteriological, rickettsiae, fungal, or protein -- that can cause damage to or death of humans, other animals, or plants." Toxins are "the harmful chemicals that can be produced by bacterial, marine organisms, fungi, plants, and animals." Biological and toxin weapons (BTW) are devices, such as aerosol sprayers or munitions, designed to deliver biological agents to a target population. This essay details the production of such biological and toxin agents, followed by a description of their weaponization and delivery to a target population. Some examples of the delivery means of BTW agents are placing agents into the water system or food supply, the release of disease-carrying insects or animals into a target population, the inoculation of a few individuals with highly infectious disease likely to spread, or a mechanical means devised to remotely and quickly deliver an aerosol cloud to a specific location. Because BTW agents are relatively simple and inexpensive to produce without detection, potential users include nations, groups, and individuals. The United States does not have measures that can effectively prevent or neutralize the effects of all BTW agents, although it does have sensors or detectors that can indicate when such agents are used. The war now being conducted by the United States against terrorism offers the best opportunity to end support abroad for terrorist groups and thus diminish the numbers and power of terrorists, but terrorism will not be ended by these efforts. The threat of terrorist use of BTW use against U.S. civilians and military will remain. The United States should undertake BTW research to better understand what is possible in this realm; smallpox vaccine should be manufactured and administered on a fast track; on-the-spot tools should be developed to diagnose plant and animal diseases; the Biosafety level 3 and 4 capabilities of the USDA must be expanded and modernized; veterinary science curricula should be revamped to emphasize large-scale animal husbandry and foreign and exotic disease recognition and treatment; and incentives should be provided to farmers to diversify crops and to intersperse crop types to provide natural barriers against the spread of disease. 45 notes