Earth is a dynamic planet, and the most geologically hazardous areas on Earth are Subduction zones. Activity in subduction zones may be sudden and violent, often with dramatic societal consequences. In addition, subduction zones are crucial for understanding the Earth as a planet, controlling the circulation of material from the surface back into the mantle. This course is a graduate-level survey intended for students that are concerned with earth processes at subduction zones. The course integrates principles of geology, geophysics, geochemistry, experimental petrology, mineral physics, geodynamics, and seismology. This course will review the current state of scientific knowledge for subduction on Earth. Topics range from the physics and chemistry of downgoing slabs from the surface to the deep mantle, mantle flow and structure in the wedge, earthquakes and deformation, melting and volcanism at arcs, and the geology of subduction initiation. Prerequisites: permission of instructor. SP 2021: Hybrid instruction; Synchronous each meeting (asynchronous options available).