A symposium presenting results from the Turkish Dilatancy Projects (TDP) was held at the British Geological Survey, Edinburgh, June 29 to July 1, 1987. These results, interpreting shear-wave splitting in terms of stress-aligned fluid-filled microcracks throughout the rock mass, are thought to be an important advance toward establishing routine techniques for the prediction of earthquakes. The meeting was stimulating with wide-ranging discussions of reports by several groups on observations in Turkey and elsewhere, and of potential applications to predicting earthquakes. The commercial prospect of using shear waves to investigate the internal structure of hydrocarbon and geothermal reservoirs was also discussed.