The great Sumatra–Andaman earthquake of 26 December 2004 (UTC 00:58:53) was a momentous event, whether measured by scientific or human standards. Sadly, what is currently regarded as the third largest earthquake in recorded history led to the worst tsunami disaster in recorded history, with the loss of more than 200,000 lives and devastation throughout the Bay of Bengal. About three months later, on 28 March 2005, the Nias–Simeulue earthquake, near the southern end of the 2004 rupture, shocked the region again. Fortunately, this Mw 8.7 earthquake, the second largest earthquake in the past decade, was less destructive. These earthquakes and resulting tsunamis have been a sobering reminder to many in the community of earthquake scientists that the subject of our professional lives can have enormous impact on humanity. Hopefully, the legacy of the science presented in this volume will be a greater understanding of earthquake and tsunami processes that will be useful in advancing the resilience of our communities to Nature’s violence.