The purpose of this paper is to introduce the reader to the active sun as a source of disturbance that affect the magnetic field measured at the earth's surface. Included under this topic are the general sun's properties, solar surface activity centers and characteristics of the solar field and ejecta flowing into interplanetary space.

This report is an introduction to solar-terrestrial phenomena for those with no special background in astrophysics or solar astronomy. Discussions of physics have been kept to a minimum, with emphasis on phenomonology instead. An individual completely unfamiliar with solar events should, after reading this volume, be able to read and understand the SESC Report and Forecast of Solar Geophysical Activity and be able to apply its contents to his particular area of concern. This volume is also intended as a quick reference work for Skylab ATM Principal Investigator Teams to assist them in using the ATM data book. For that reason, a list of abbreviations used in forecasts and observatory reports is included. Subjects discussed are solar structure and processes, solar activity, and solar-terrestrial relations. There is a brief description of the Space Environment Services Center's activities.