The report presents a series of specific theoretical studies directed toward the solution of jet noise generation and radiation, upstream noise radiation and combustion noise generation. Three theories are presented. Lilley's work is a new theory of jet noise generation, based on identification of acoustic and source generation terms. The acoustic 'converted wave equation' derived includes the Pridmore-Brown/Mungur shear refraction term. Plumblee presents a theoretical analysis and numerical solution techniques for solving for the radiation field from a source within a jet flow and specifically deals with radiation from an acoustic distribution initally specified at the end of a circular exhaust duct termination through the jet flow to the surrounding medium. Finally, Strahle presents a theory on afterburner type combustion noise generation and radiation. Order of magnitude analyses are made in an attempt to estimate acoustic power levels and refraction effects are also investigated. (Author).