Knowledge of thermodynamic data of polymer solutions is a necessity for industrial and laboratory processes. Furthermore, such data serve as essential tools for understanding the physical behavior of polymer solutions, for studying intermolecular interactions, and for gaining insights into the molecular nature of mixtures. They also provide the necessary basis for any developments of theoretical thermodynamic models. Scientists and engineers in academic and industrial research need such data and will benefit from a careful collection of existing data. However, the database for polymer solutions is still modest in comparison with the enormous amount of data for low-molecular mixtures, and the specialized database for polymer solutions at elevated pressures is even smaller. On the other hand, especially polymer solutions in supercritical fluids are gaining increasing interest (1994MCH, 1997KIR) because of their unique physical properties, and thermodynamic data at elevated pressures are needed for optimizing applications, e.g., separation operations of complex mixtures in the high-pressure synthesis of polymers, recovery of polymer wastes, precipitation, fractionation and purification of polymers, and polymers in green chemistry processes.