This report provides the first systematic look at the health effects of exposures to emissions from a new-technology heavy-duty diesel engine. Included in this report are results obtained in rats and mice exposed for 1 and 3 months (and some results in rats at 12 months) to exhaust from a 2007-compliant diesel engine with aftertreatment to reduce particulate matter concentrations. Part 1 describes the core inhalation study by Drs. Jake McDonald and Joe Mauderly of the Lovelace Respiratory Research Institute, with results on general organ toxicity, lung histopathology, pulmonary function, and markers of inflammation and oxidative stress in blood and lung lavage fluid. Parts 2 and 3 describe studies by Drs. Jeffrey Bemis of Litron Laboratories and Lance Hallberg of the University of Texas Medical Branch, respectively, assessing genotoxic endpoints in the exposed rodents. Part 4 describes a study of vascular markers by Daniel Conklin of the University of Louisville. The Preface to this report contains background information about the planning and designing of the study, including decisions regarding the diesel exhaust dilutions and the choice of rodent strains.