An up-to-date progress report on the current status of solar-terrestrial relation studies with an emphasis on observations by the Russian Interball spacecraft and the Czech Magion subsatellites. Papers in the volume describe the various spacecraft in the International Solar-Terrestrial Program and the research questions that they are being used to address. The emphasis is on correlative studies employing multiple instruments and multiple spacecraft. The book begins with a description of each spacecraft active in 1998 and describes the roles they can play in correlative studies. This is followed by an up-to-date status report concerning ongoing studies of the solar wind, foreshock, bow shock, magnetopause, magnetotail, and ionosphere, with an emphasis on the observations made by the four Interball spacecraft. Readership: Researchers and graduate students of space physics and astrophysics.