The 2010 tsunamis generated in Haiti, Chile, and Indonesia caused various damage on the coasts. In the past, the 1755 Lisbon, 1964 Alaska, and 2003 Algeria earthquakes also generated damaging tsunamis. This volume contains an introduction and 18 papers, mostly presented at the 25th International Tsunami Symposium held 1-4 July 2011. They report the above tsunamis and discuss tsunami DART observations, warning systems, risk management in the Pacific, modelling of earthquake and landslide tsunamis, and probabilistic tsunami hazard assessment.