The EISCAT Facility.- The Viking Satellite.- Physics of the High Latitude Ionosphere.- The Role of the Auroral Ionosphere in Magnetospheric Substorms.- Characteristics of the Polar Cap at Ionospheric Levels and Present Understanding of the Physical Processes that give Rise to these Characteristics.- The Low Altitude Cleft: Plasma Entry and Magnetospheric Topology.- Incoherent-Scatter Radar Measurements of Electric Field and Plasma in the Auroral Ionosphere.- Irregularities and Instabilities in the Auroral F-Region.- Significance of Scatter Radar Studies of E and F Region Irregularities at High Latitudes.- Ionospheric Modification and Stimulated Emissions.- Plasma Physics on Auroral Field Lines: The Formation of Ion Conic Distributions.- Solar Wind Influence on the High Latitude Ionosphere.- Dependence of the High-Latitude Ionospheric Fields and Plasma Characteristics on the Properties of the Interplanetary Medium.- Solar Wind-Magnetosphere Energy Coupling.- Interpretation of Observed Relations between Solar Wind Characteristics and Effects at Ionospheric Altitudes.- High Latitude Magnetospheric Physics above a few Thousand Kilometers.- Cold Plasma Distribution above a few Thousand Kilometers at High Latitudes.- The Hot Ion Composition, Energy, and Pitch Angle Characteristics above the Auroral Zone Ionosphere.- The Hot Electrons in and above the Auroral Ionosphere: Observations and Physical Implications.- On the Composition of the Ring Current and the Plasmasheet and what it tells about the Sources of these Hot Plasma Populations.- Birkeland Currents: Present Understanding and some Remaining Questions.- High Latitude Electromagnetic Plasma Wave Emission.- Correlation of Auroral Kilometric Radiation with Visual Auroras and with Birkeland Currents.- A Review of Electrostatic Waves in the Topside Ionosphere.- Effects of Heavy Ions on Microscopic Plasma Physics in the Magnetosphere.- Anomalous Resistivity on Auroral Field Lines and its Role in Auroral Particle Acceleratilƒ%