With a surface area of 100 m2 and a capacity of some 6 L, approximately 10% of which is exchanged during each of the 15 breaths taken every minute, the lungs are the most likely portal for systemic intoxication by airborne pathogens and toxins. The contents of these chapters are intended to provide information for the protection of human health from the harmful effects of airborne pathogens and toxins. Continued research and development will undoubtedly change some of these perspectives. This is especially true in the areas of detection and protection. Consequently, the work presented here is a starting point for further enhancement of the quality of life in all parts of Planet Earth.