The primary objective of the project was to determine the composition of Cerro Negro and other heavy (low API gravity) crude oils. Initially, existing analytical methodology for separation and analysis of conventional and heavy petroleum was evaluated through its application to Cerro Negro and other petroleum, as well as coal-derived syncrudes. Although selected methods and/or elements of methods performed well toward their given task, the need for an integrated scheme for systematic separation and analysis of very complex materials like Cerro Negro became apparent even in the early phases of the work. Thus, a major portion of the project became development of such a scheme. Figure 1 shows the resulting sequence of separation and analysis steps developed. Because of its general applicability and documented performance on Cerro Negro and other crudes, the methodology depicted in the figure (described in detail in the accompanying chapters) represents the most significant product from the research. While some elements of the scheme consist of conventional techniques (e.g., distillation), others encompass significantly improved versions of earlier methods (e.g., nonaqueous ion exchange LC) or novel procedures (e.g., schemes 1-4).