These proceedings are based upon in~roductory talks, re- search repor~s and discussions at the NATO Advanced Work- shop on ELECTROMAGNETIC COUPLING IN THE POLAR CLEFTS AND CAPS, held at Lillehammer, Norway, 20-24th September 1988. By this book we will make the information which was pro- vided to the participants of the workshop, accessible to a wider audience. Electromagnetic processes governing particle, momen- tum, and energy transfer from the solar wind via the magne- tosphere and into the earth's upper atmosphere are the main topics of solar-terrestrial research. Due to the peculiar...