Model-driven software development has all chances to turn software development into software engineering. But this requires not only mature methodologies but also engineering models. An engineering model should satisfy five key characteristics, namely, abstraction, understandability, accuracy, predictiveness and inexpensiveness. This chapter discusses capabilities of a Topological Functioning Model (TFM) as such an engineering model for the purposes of domain analysis and software development in common. The TFM has functional and topological properties. The functional properties are cause-effect relations, cycle structure, inputs, and outputs. The topological properties are connectedness, closure, neighborhood, and continuous mapping. Thanks to its formal mathematical foundations, the TFM completely satisfies the mentioned characteristics of engineering models that is illustrated in the chapter.