Subduction zones present many facades to those that observe them. From obvious features to obscure yet important processes, there are many aspects of subduction zones to observe and explain. Notable examples of obvious features are volcanoes, earthquakes, mountain belts, and deep sea trenches; while on the other hand, the unseen process of sediment subduction can produce long-term effects on the Earth’s geochemical reservoirs. Indeed, most disciplines of the earth sciences have reasons to study subduction zones, and consequently all disciplines can make contributions to our understanding of subduction zones.