Pulmonary Immunotoxicology comprises four sections. The first provides basic background concepts essential for understanding pulmonary immunotoxicology, including discussions of the normal structure and function of the respiratory system, its basic immunology, and the manner by which inhaled particles and gases are removed from the air and deposited upon respiratory tract surfaces. The second section provides an overview of the major types of pathological consequences which can arise from immunomodulation within the respiratory tract, including hypersensitivity and asthma, inflammation and fibrosis, as well as immunosuppression and autoimmunity. The third section, which comprises the largest portion of the book, deals specifically with major classes of airborne agents that are known to alter the immune function of the respiratory tract. These are arranged into major classes: organic agents, metals, gases, particles, biologics, and complex mixtures. The fourth and final section of the book explores the area of risk assessment, including discussions of the basic concepts of risk assessment as they apply specifically to immunotoxicologic effects upon the lungs, and the use of biomarkers as indices of potential pulmonary immunotoxic responses to inhaled materials.