The solar wind has long been studied by a variety of indirect techniques; indeed, it was actually ‘discovered’ by Biermann through analysis of comet tail observations. Of course, direct spacecraft observations are vastly superior when and where they are available, but the methods are complementary. Ground-based methods are used to extend our information, both to inaccessible regions near the sun and out of the ecliptic and to span a much larger time period. Although interesting and important results are coming from such work, surprisingly little attention has been paid to the use of spacecraft data to ‘calibrate’ the ground-based data in regions of overlap. This workshop, which was held in Moscow, April 5–10,1979, is a first step in this direction. The meeting was widely attended by Soviet and East European scientists, but participation by North American and West Europeans was weakened by almost simultaneous meetings on related subjects.