This chapter gives an introduction to magnetization dynamics in ferro- and ferrimagnetic materials. Our focus will be on spin waves, a special case of magnetization dynamics of small angle oscillations of the magnetization in an otherwise uniformly magnetized film. If damping is low, then a rich array of wave-like phenomena occurs, showing many features that resemble classical, optical wave propagation. A large class of spin-based computing devices is built on the idea of using such waves for computation. (Parts of this chapter are based on Dr. Adam Papp’s dissertation work, used with permission.)