Before outlining the contents of this chapter, a comment about terminology is in order. There is no consensus about terms used to refer to the types of models to be presented in this chapter. Primarily for historical reasons, the term path analysis has been used to refer to the analysis of causal models when single indicators are employed for each of the variables in the model (see Pedhazur, 1982, Chapter 15, and references given therein). Because of the great popularity of the LISREL computer program (Joreskog & Sorbom, 1989) for the analysis of causal models, some researchers and authors refer to them as LISREL, or LISREL-type, models. (Users of this program have even been referred to as LISRELites.) Among other terms used are causal modeling, analysis of covariance structures, latent variable models, structural modeling, and structural equation modeling (SEM). Along with various authors, we prefer the latter term.