Conspectus The review improves our understandingof how electrostatic interactionsin the electrolyte, gas phase, and on surfaces can drive the fragmentationand assembly of particles. This is achieved through the overview ofour advanced theoretical and computational modeling toolbox suitablefor interpretation of experimental observations and discovery of novel,tunable assemblies and architectures. In the past decade, we haveproduced a significant, fundamental body of work on the developmentof comprehensive theories based on a rigorous mathematical foundation.These solutions are capable of accurate predictions of electrostaticinteractions between dielectric particles of arbitrary size, anisotropy,composition, and charge, interacting in solvents, ionized medium,and on surfaces. We have applied the developed electrostatic approachesto describe physical and chemical phenomena in dusty plasma and planetaryenvironments, in Coulomb fission and electrospray ionization processes,and in soft matter, including a counterintuitive but widespread attractionbetween like-charged particles. Despite its long history, thesearch for accurate methods to providea deeper understanding of electrostatic interactions remains a subjectof significant interest, as manifested by a constant stream of theoreticaland experimental publications. While major international effort inthis area has focused predominantly on the computational modelingof biocatalytic and biochemical performance, we have expanded theboundaries of accuracy, generality, and applicability of underlyingtheories. Simple solvation models, often used in calculating the electrostaticcomponent of molecular solvation energy and polarization effects ofsolvent, rarely go beyond the induced dipole approximation becauseof computational costs. These approximations are generally adequateat larger separation distances; however, as particles approach thetouching point, more advanced charged-induced multipolar descriptionsof the electrostatic interactions are required to describe accuratelya collective behavior of polarizable neutral and charged particles.At short separations, the electrostatic forces involving polarizabledielectric and conducting particles become nonadditive which necessitatesfurther developments of quantitatively accurate many-body approaches.In applications, the electrostatic response of materials is commonlycontrolled by externally applied electric fields, an additional complexmany-body problem that we have addressed most recently, both theoreticallyand numerically. This review reports on the most significantresults and conclusionsunderpinning these recent advances in electrostatic theory and itsapplications. We first discuss the limitations of classical approachesto interpreting electrostatic phenomena in electrolytes and complexplasmas, leading to an extended analytical theory suitable for accurateestimation of the electrostatic forces in a dilute solution of a strongelectrolyte. We then introduce the concept and numerical realizationof many-body electrostatic theory focusing on its performance in selectedexperimental cases. These experiments underpin, among other applications,electrostatic self-assembly of two-dimensional lattice structures,melting of ionic colloidal crystals in an external electric field,and coalescence of charged clusters.