  Aequous dielectrics are ubiquitous in soft- and bio-nano matter systems. The
theoretical description of such systems in terms of continuum (`macroscopic')
theory remains a serious challenge. In this perspective we first review the
existing continuum phenomenological approaches that have been developed in the
past decades. In order to describe a path to advance continuum theory beyond
these approaches we then take recourse to the Onsager-Dupuis theory of the
dielectric behaviour of ice, which, for the case of a solid dielectric,
exemplified important conceptual issues we deem relevant for the development of
a more fundamental continuum theory of liquid dielectrics. Subsequently, we
discuss our recently proposed continuum field theory of structured dielectrics,
which provides a generalized approach to the dielectric behavior of such
systems.
