Dynamics of Clusters of Galaxies

The abundance and internal characteristics of rich clusters of galaxies can provide useful constraints on models of large--scale structure formation. This article will review some recent three dimensional, multi--fluid simulations of cluster dynamics and discuss their impact on issues raised from optical and X-ray observations of clusters. In `bottom--up' formation scenarios (such as the ubiquitous cold dark matter model), galaxies form before rich clusters; hence, cluster formation is intimately linked to galaxy formation which, in turn, is tied to star formation. I will examine two issues which appear relatively insensitive to galaxy/star formation --- the baryon fraction in clusters and the connection between X--ray morphology and $\Omega_o$ --- and end with a topic that is intimately linked to it --- dynamical biases in the cluster galaxy population.