Published by the American Geophysical Union as part of the Antarctic Research Series, Volume 70. The Long-Term Ecological Research (LTER) Program was established in 1981 by the United States National Science Foundation in recognition of the need to study ecological processes over time spans longer than those of most research grants. The LTER Network now consists of 18 sites that span a variety of ecosystem types in the continental United States, Alaska, Puerto Rico, and Antarctica. The addition of the Palmer LTER at Palmer Station, Antarctica in October 1990 extended the geographical and ecological range of the LTER Network and provided the opportunity to link physical and ecological processes in the northern and southern hemispheres. One criterion for establishment of a LTER site is the existence of historical data and observations that can provide a basis for guiding research programs. Thus, the intent of this volume is to bring together meteorological, hydrographical, biological and ecological observations made in the general area west of the Antarctic Peninsula and to discuss the processes underlying the observations. This compilation of available data and observations in conjunction with the present understanding of processes provides the foundation for long?]term studies of the ecosystem in the western Antarctic Peninsula region.