The plan for my first talk is a survey of the basic issues in
 accretion disk dynamics.  It will begin with some simple scaling
 arguments and then continue with a presentation of what one can learn
 from simple analytic models, including the Shakura-Sunyaev
 alpha-model.  The latter part will present the modern view, in which
 MHD turbulence plays a key role and numerical simulations are
 essential to gaining quantitative results.  New conclusions based on
 both general relativistic MHD simulations of disks around black holes
 and radiation/MHD simulations of the internal structure of disks will
 be the last topic.