Among the least understood processes which contribute to the formation of igneous rocks are the mechanisms by which magmas move within and on the surface of the earth. Understanding these phenomena requires learning the physics of deformable materials. The purpose of this chapter is to introduce and review the equations describing fluid flow, to provide a qualitative understanding of their implications for magma behavior and to solve a single, simple application. This application, although somewhat unrealistic, displays the techniques and problems of modeling magma transport.