The research submersible Alvin is operated by the Woods Hole Oceanographic Institution in support of scientific programs undertaken by US oceanographers. The boat carries a pilot and two scientists and has made major contributions to US oceanography, ranging from research on the biology of the deep sea to the formation of the ocean crust. It is the only deep diving submersible routinely available to the US community. This year will mark the 25th anniversary of Alvin operations and the present award will support a symposium to summarize the scientific accomplishments of this unique national resource. The symposium is being jointly supported by the National Science Foundation, the National Oceanic and Atmospheric Administration and the Office of Naval Research.