  A simple field theory approach is developed to model the properties of
charged, dielectric bodies and their associated counterions. This predictive
theory is able to accurately describe the properties of systems (as compared to
computer simulation data) from the weak coupling limit, where the
Poisson-Boltzmann theory works well, through to the strong coupling limit. In
particular, it is able to quantitatively describe the attraction between
like-charged plates and the influence of image charge interactions.
