This chapter traced the evolution of the foundations of transport network equilibrium modeling and analysis, with a focus on the principle methodological advances. In particular, an attempt has been made to set out in accessible fashion rigorous approaches to the formulation of a variety of traffic network equilibrium models and to establish relationships between the models as well as those that are closely linked such as spatial price equilibrium models. It should be emphasized that this topic is a very active area of research as well as practice. It should also be highlighted and further emphasized that traffic network equilibrium modeling and analysis provide a powerful framework for decision-making on complex networks. Indeed, given the interrelationships between telecommunications and transportation network’s in today’s network economy, it can be expected further synergies and advances in the study of such foundational networks. Of particular promise are the areas of multicriteria decision-making on networks, multitiered networks, as well as multilevel networks (in the form of transportation/logistical/financial/informational networks), formally referred to as supernetworks.