The notion that "like charges repel and opposite charges attract" is familiar to everyone, but electrostatic attraction between like-charged objects is also possible due to their mutual polarization. A problem of fundamental and general interest is how electrostatic interactions are influenced by the presence of a polarisable medium, for example water. We overview a comprehensive theory [1,2] with universal relevance to the electrostatic properties of closely interacting particles of arbitrary size and charge , which has been extended recently to modelling electrostatic interactions in solvents  and ionized medium . This development contributes to the design of thin films and surface assemblies with novel properties. We find that the nature of electrostatic interaction is determined by how polarizable the particle and surface are as compared to the medium. The findings allow a comprehensive understanding of electrostatic particle-particle and particle-surface interactions in many areas of science, ranging from Coulomb fission of charged clusters [6,7] to aerosol growth in planetary atmospheres .