The National Bureau of Standards has embarked on a special program to unify and accelerate its research on hot gases. This work will provide data and theory presently required for the quantitative interpretation of astrophysical and geophysical observations and the measurement of properties of plasmas in the laboratory. The data, measurement techniques, and theoretical methods of analysis draw on activities in the fields on atomic and molecular physics, statistical mechanics and thermodynamics, fluid mechanics, and theoretical astrophysics and geophysics. Both the Washington and Boulder laboratories of the NBS are participating. This note describes the technical objectives of the program and includes in appendices a selected list of papers published at the NBS for the period 1955-1959 and a partial list of Bureau participants.