The purpose of this chapter is to discuss from an SEM standpoint some of the topics we first introduced from a MR orientation. In Part 2, we discussed testing for interactions between categorical and continuous variables using multigroup analysis in SEM. In this chapter, we will see how to test for interactions between continuous latent variables, thus extending the topic first presented (from a MR orientation) in Chapter 8. In Chapter 11, I briefly presented multilevel modeling from a regression orientation. Here, we will see how to analyze these models in an SEM context, with both measured and latent variables.