The world's largest volcanic eruptions are typically associated with large collapse calderas, some of which have diameters >50 km. Many volcanic systems forming calderas are associated with major ore deposits and geothermal energy resources. Calderas also provide key insights into the generation and evolution of large-volume silicic magma bodies. In 1983, a weeklong session was convened during the fall meeting of the American Geophysical Union to celebrate the 100th anniversary of the 1883 Krakatau eruption. This volume contains 39 papers from these sessions that were published in the Journal of Geophysical Research (Solid Earth).