or to one that is in equilibrium with coexisting predominantly oil and/or aqueous phases, or even to other non-isotropic phases. As in the binary systems (water/surfactant or oil/surfactant), self-assembled structures of different types can be formed, ranging, for example, from (inverted) spherical and cylindrical micelles to lamellar phases and bicontinuous microemulsions, which may coexist with predominantly oil or aqueous phases.