* The 20th century saw the introduction of many new technologies for warfare. Among the most controversial were poison gases, and pathogens and biotoxins used as weapons. There is a widespread detestation of chemical and biological warfare (CBW), but despite many attempts to limit the spread of such weapons, the ease with which they can be developed and their sheer destructive potential make them attractive to any government that wants to obtain a military advantage. It is likely, then, that such weapons will be a significant factor in the 21st century. This document provides a short history of CB warfare. It is also available in a downloadable archive, formatted in HTML, for reading on a tablet or other viewer.