The Study of Travelling Interplanetary Phenomena (STIP) was formally established by the International Council of Scientific Unions' Special Committee on Solar-Terrestrial Physics (SCOSTEP) in August 1973 with M. Dryer as Convenor and M. A. Shea as Secretary. The scientific objec- tives of STIP are the study and search for understanding of quiet (i.e. normal or background) and active periods in the interplanetary medium. The concepts of informal, extemporaneous interdisciplinary research is continuo~sly emphasised, and these concepts have proved to be extremely successful in conducting the very productive studies undertaken by the members. About 200 scientists are actively participating in STIP, their interests ranging from solar physics (insofar as it concerns the initi- ation of phenomena which move out from the Sun) to the observation and study of comets and planetary magneto spheres and ionospheres. Solar wind plasma and fields, solar and galactic cosmic rays, interstellar interactions, solar radio astronomy and interplanetary scintillations of discrete radio sources are among the topics of interest.