Probably no other event has generated the level of interest and excitement within the atmospheric science community as the publication of observations in 1985 from the British Antarctic Survey team from Halley Bay. Those observations indicated large, unexplained depletion of column ozone above Antarctica during austral spring. A ground-based campaign, called the National Ozone Expedition I (NOZE I), was organized during 1986, followed by an airborne campaign, the Airborne Antarctic Ozone Experiment (AAOE) and a second ground-based expedition (NOZE II) in 1987. After a period of intense analysis, a consensus view developed that the depletion resulted largely from chlorine-catalyzed chemistry within the isolated and highly perturbed polar vortex. The possibility that similar processes might occur in polar regions during northern hemisphere winter and spring provided the impetus for the Airborne Arctic Stratospheric Experiment (AASE) in 1989. A large number of scientific papers resulted from these concentrated campaigns, many of which were published in special issues of the Journal of Geophysical Research and Geophysical Research Letters. Subsequently, much additional data analysis (from the various campaigns and other sources) and many modeling efforts have been undertaken. The present special issue provides a focused form for some of the subsequent work, related to polar ozone. A total of 23 papers have been considered for inclusion in the special issue. These papers underwent the normal JGR reviewing process. With an impending polar mission to the Arctic in the fall of 1991, it was a Herculean effort for many of the authors and reviewers to participate in the preparation of this issue. We are therefore most grateful to our colleagues for their assistance. We trust that this issue will continue the ''saga'' of polar ozone depletion and will be but an intermediate step, as the scientific community unravels the complex and fascinating chemical, dynamical, and radiative processes at work in the polar stratosphere. ¿ American Geophysical Union 1992