The European Space Research Organisation put its first satellite into orbit in March 1968 and was successful with two more before the end of that year. It was not entirely surprising therefore that the third annual ESLAB/ESRIN Symposium should in some way deal with the results obtained. This book is the Proceedings of that Sym posium which, for reasons which Dr. Trendelenburg explains in the introductory talk, concentrated on intercorrelating phenomena occurring during solar events and in particular during the event of 25 February 1969. It is generally acknowledged that space data could yield...