An approach to understanding the spontaneous and induced lesions in the respiratory system of laboratory animals, especially the rat, mouse and hamster. Current understanding of the nature and significance of pathologic lesions is probed throughout this volume : The Upper Respiratory System.- Histology, Ultrastructure, Embryology, Function.- Normal Morphology of the Nasal Passages in Laboratory Rodents.- Proliferative and Metaplastic Lesions in Nonolfactory Nasal Epithelia Induced by Inhaled Chemicals.- Nonneoplastic Lesions of the Olfactory Mucosa.- Microscopic Anatomy of Toxicologically Important Regions of the Larynx of the Rat, Mouse, and Hamster.- Effects of Xenobiotics on the Larynx of the Rat, Mouse and Hamster.- Development of Syrian Golden Hamster Tracheal Epithelium During Prenatal and Immediate Postnatal Stages.- Neoplasms.- Morphological Response of Respiratory Epithelium to Carcinogens, Syrian Hamster (Mesocricetus auratus W.).- Nasal Neoplasia.- Hemangiosarcoma, Nasal Cavity, Mouse.- Neuroendocrine Hyperplasias and Tumors, Larynx and Trachea, Syrian Hamster.- Lesions Due to Infection.- Murine Respiratory Mycoplasmosis, Rat and Mouse.- Rat Coronavirus Infection, Upper Respiratory Tract, Rat.- The Lung (Bronchi, Bronchioles, Alveolar Ducts, Alveoli, Pleura).- Histology, Ultrastruture, Function.- Structure and Function of the Lung.- In Vitro Differentiation of an Epithelial Stem Cell Line Derived from the Fetal Syrian Hamster Lung.- Comparative Aspects of Pulmonary Carcinogenesis.- Alveolar/Bronchiolar Hyperplasia, Adenoma and Carcinoma, Lung, Rat.- Naturally Occurring Pulmonary Tumors in Rodents.- Squamous Cell Carcinoma, Lung, Rat.- Radiation-Induced Squamous Cell Carcinoma, Lung, Rat.- Radiation-Induced Adenocarcinoma, Lung, Rat.- Radiation-Induced Sarcomas, Lung, Rat.- Radiation-Induced Adenosquamous Carcinoma, Lung, Rat.- Pleural Mesothelioma, Syrian Hamster.- Metastatic Tumors, Lung, Mouse.- Nonneoplastic Lesions.- Bleomycin-Induced Injury, Mouse: A Model for Lung Injury.- Fibroblast Interactions with Epithelial Cells in Lung Injury and Repair.- Fibroblast Interactions with Alveolar and Interstitial Macrophages. Models: Silicosis and Asbestosis in the Mouse.- Pulmonary Lipidosis, Rat.- Alveolar Lipoproteinosis, Rat.- Fly Ash Pneumoconiosis, Hamster.- Asbestosis, Hamster.- Squamous Metaplasia, Lung, Rat.- Pulmonary Hair Embolism, Rat.- Goblet Cell Metaplasia, Lung, Rat.- Lesions Due to Infection.- Sendai Virus Infection, Lung, Mouse, and Rat.- Pneumonia Virus of Mice Infection, Lung, Mouse, and Rat.- Rat Coronavirus Infection, Lung, Rat David G. Brownstein.- Cilia-Associated Respiratory Bacillus Infection, Rat, Mouse, and Rabbit.- Pneumocystosis, Lung, Rat.- Toxoplasmosis, Lung, Mouse, and Hamster.- Aspergillosis and Mucormycosis, Lung, Rat.