: A Summary Description of Aeronomy.- The Neutral and Ion Chemistry of the Upper Atmosphere.- A. Neutral and ionized atmospheric structure and composition.- B. Interactions of solar radiations with atmospheric gases.- C. Collision processes and chemical reactions.- D. Laboratory measurements of relevant rate coefficients.- E. Experimental methods for measurement of neutral and ion composition.- F. Aeronomical models of neutral composition.- G. Aeronomical models of ion composition.- H. The production of excited species and their roles in atmospheric and ionospheric processes.- General references.- Diffusion in the High Atmosphere.- I. Introduction and the general theory of diffusion.- II. Diffusive equilibrium, mixing, and turbulence in the high atmosphere.- III. Vertical distributions of molecular and atomic oxygen.- IV. Ambipolar diffusion including the formation of the F2-layer.- V. Vertical distributions of minor constituents in the high atmosphere.- General references.- Interaction of Neutral and Plasma Motions in the Ionosphere.- A. Introduction.- B. Fundamental equations.- C. Calculation of wind velocities.- D. Observed wind velocities.- E. Effects of winds on the ionosphere.- F. Effects of plasma motions on the neutral wind.- G. Conclusion.- List of main symbols.- General references.- Extreme Ultraviolet Observational Data on the Solar Spectrum.- I. Spectral observations.- II XUV solar images.- III. Observation of x-ray solar radiation over wide spectral ranges.- IV. Identification and prediction of extreme ultraviolet lines.- V. Chemical composition of the solar atmosphere derived from EUV data.- General references.