Magmatic arcs result from subduction along a convergent plate boundary. The relative movement of the plates is rarely orthogonal and there is often concurrent deformation in the back-arc region. Consequently, there is generally an interplay between tectonism and magmatism in magmatic arcs. This talk discusses a series of magmatic arcs that I have studied in my career, including the Cretaceous Sierra Nevada magmatic arc in California, the active magmatic arc in El Salvador and Guatemala, and the Laguna de Maule volcanic field in the active Andean arc in Chile. The short summary is that granite magmas appear to need strike-slip faults to rise through the crust, deformation follows the magmatism in almost all cases, the granitic plutons are incrementally emplaced, and the deformation in the back-arc has a major impact on the magmatic arc.