This chapter applies the thermodynamic and rheological theories developed so far to the specific important network-forming associating polymer solutions. The topics include modification of the phase separation and gelation of associating polymers by added surfactants, transition from intramolecular association to intermolecular association, competitive and coexisting hydration and hydrophobic association, and thermoreversible gelation strongly coupled to the polymer conformational change. With an increase in the number of components, or the degree of freedom in the system, phase transitions and flow properties become complex. However, the basic ideas to treat them stay within the fundamental theoretical framework presented in the preceding chapters. All systems are modeled from a unified point of view.