This special section contains papers from the International Workshop on Variable Phenomena in Jovian Planetary Systems held in Annapolis, Maryland, July 13--16, 1992. As Galileo approaches Jupiter and the planning for the Cassini mission to Saturn progresses, the time was appropriate to assess the current knowledge of Jovian planetary systems and to evaluate what the near-Earth observing community could do to optimize the observations from these missions. This is the second such workshop; the first was held in Flagstaff, Arizona, on August 25--27, 1987 et al., 1989>. The recent workshop occurred just 31/2 years before Galileo's Jupiter orbit insertion (JOI) and provided an opportunity for the community to examine and define the relevant observational, theoretical, and laboratory research in time to influence final planning for the mission science sequences. The workshop was organized as part of the International Jupiter Watch and was sponsored by the Division of Planetary Sciences of the American Astronomical Society and the Planetology Section of AGU. Support was provided by the Galileo Project and NASA Headquarters Solar System Exploration Division. More than 100 scientists from Europe, Asia, the Middle East, and the former Soviet Union participated. ¿ American Geophysical Union 1992