LISREL-type structural equation modeling is a powerful statistical technique that seems appropriate for social science variables which are complex and difficult to measure. The literature on the specification, estimation, and testing of such models is voluminous. The greatest proportion of this literature, however, focuses on the technical aspects of LISREL, and many are far advanced in statistical sophistication so as to be of little or no help to the novice modeler. This paper presents a "philosophical" approach to structural equation modeling and examines some of the basic concepts and assumptions underlying the formulation of these models. The rationales for the structural equation model and the measurement model are outlined, and the foundations of specification and interpretation clarified. As part of the SPSS-X package, LISREL will be readily available to many applied researchers. With this heightened availability of a complicated statistical procedure will undoubtedly come many misuses and abuses. Social scientists should become familiar with the theoretical premises of the method. (Author/JAZ)