A primary value of the Textbook of Military Medicine series is to preserve the lessons of past wars and, by so doing, demonstrate how current doctrine is built on knowledge that was gained at so high a cost. Medical officers should read this volume, Medical Aspects of Chemical and Biological Warfare, and learn its lessons well. Civilians expect that we in the military will know how to manage chemical and biological casualties. Indeed, if we do not, then who will? The nation expects us to be prepared to defend against all attacks and will be unforgiving of any incapacity on our part.