Space, whether interplanetary or interstellar, is filled with plasma or ionized gas. The success of space exploration must count heavily on the study and understanding ofthe plasma. With this view, the Symposium ofPlasma Space Science was held at The Catholic University of America in Washington, D.C., in cooperation with the National Aeronautics and Space Administration and the Goddard Space Flight Center, June 11-14, 1963. The symposium was organized by Dr. C. C. Chang as director and Dr. Y. C. Whang as assistant director. The proceedings consist of four parts. The first part describes the...