This is a phased, investigator initiated, multi-center cooperative study. Its major purpose is to answer, using modern pathobiological approaches, some of the perplexing questions concerning the pathogenesis of atherosclerosis in childhood and young adulthood. Autopsies on young persons (15 to 35) dying from trauma will be performed so that their coronary arteries and aortas may be examined by a standard protocol. Measurements of selected lesion characteristics will be made on specified samples at designated centers by histotechnical techniques (U. Chicago), morphometry of gross and microscopic specimens (Ohio State U.), and biochemical analyses for lipids (LSU). Other ancillary studies on subsamples of cases include analyses of arterial connective tissue, surveys for the presence of viral products, and protein mapping. Administration will be coordinated by U. Chicago. Data management and statistical analyses will be performed at the Statistical Center in San Antonio. The Statistical Center will have a large part in development of the Standard Operating Protocol, forms design, sample size estimation, testing of morphological and biochemical methods to be used in the study, data management system design and operation, and data quality control. The Statistical Center will receive data from collecting centers, enter the data to computer data files, check the data for errors, monitor the data for protocol violations, and perform intermediate and final statistical analyses.