The Orion complex: A case study of interstellar matter

A compilation of current observational materials on the Orion complex is presented. A large amount of published data is compiled in the form of photographs, contour maps, diagrams, and tables. Also presented are an outline of the complex, the physical problems associated with it, the empirical models describing its behavior, and the specific methods employed to derive the physical parameters of an H II region and the dust and molecular cloud physically associated with it. Topics discussed include the morphology of the Orion region and the nature of Barnard's Loop, the ionized gas of the Orion H II/molecular complex (the Great Orion Nebula), the empirical models introduced to attempt to explain certain aspects of this region, and the second prominent H II region and molecular cloud complex of the Orion region (NGC 2024).