Abstract The Toba Caldera in Indonesia is one of the most remarkable volcanic features formed during Quaternary geologic time. Its rich history of research for over a century has yielded important information on the physical volcanology of silicic calderas and super-eruptions, geochemical evolution of silicic magma bodies, and geophysical imaging of active sub-volcanic systems. During the past 1.3 my, the Toba area has erupted intermediate composition lavas, followed by intermediate pyroclastics, three quartz-bearing silicic tuffs, and most recently, intermediate to silicic lavas. This pattern represents the incremental assembly and periodic eruption of a crustal magma body of batholithic proportions. The apparent migration of activity to the west, may have implications for the next? Toba super-eruption.